diff --git a/benchmarks/pandas/bench_boolean_array.py b/benchmarks/pandas/bench_boolean_array.py
new file mode 100644
index 00000000..8a16b8d8
--- /dev/null
+++ b/benchmarks/pandas/bench_boolean_array.py
@@ -0,0 +1,43 @@
+"""Benchmark: BooleanArray — nullable boolean extension array operations.
+N=100_000 elements with ~10% nulls using pandas BooleanArray.
+Tests: array creation, any, all, sum, and, or, invert, fillna.
+"""
+import json
+import time
+import pandas as pd
+
+N = 100_000
+WARMUP = 5
+ITERATIONS = 50
+
+# Same pattern as TS version (~10% nulls)
+raw = [(None if i % 10 == 0 else bool(i % 3 != 0)) for i in range(N)]
+raw2 = [(None if i % 7 == 0 else bool(i % 2 == 0)) for i in range(N)]
+
+
+def run():
+    a = pd.array(raw, dtype="boolean")
+    b = pd.array(raw2, dtype="boolean")
+    _ = a.any(skipna=True)
+    _ = a.all(skipna=True)
+    _ = a.sum(skipna=True)
+    _ = a & b
+    _ = a | b
+    _ = ~a
+    _ = a.fillna(False)
+
+
+for _ in range(WARMUP):
+    run()
+
+start = time.perf_counter()
+for _ in range(ITERATIONS):
+    run()
+total = (time.perf_counter() - start) * 1000
+
+print(json.dumps({
+    "function": "boolean_array",
+    "mean_ms": total / ITERATIONS,
+    "iterations": ITERATIONS,
+    "total_ms": total,
+}))
diff --git a/benchmarks/pandas/bench_first_last_valid_index.py b/benchmarks/pandas/bench_first_last_valid_index.py
new file mode 100644
index 00000000..674aab50
--- /dev/null
+++ b/benchmarks/pandas/bench_first_last_valid_index.py
@@ -0,0 +1,45 @@
+"""
+Benchmark: first_valid_index / last_valid_index
+Outputs JSON: {"function": "first_last_valid_index", "mean_ms": ..., "iterations": ..., "total_ms": ...}
+"""
+import json
+import time
+import numpy as np
+import pandas as pd
+
+N = 100_000
+
+# Series where first valid is near the start (a few NaN at beginning)
+data_start = np.where(np.arange(N) < 10, np.nan, np.arange(N, dtype=float))
+series_start = pd.Series(data_start)
+
+# Series where last valid is near the end (a few NaN at the end)
+data_end = np.where(np.arange(N) >= N - 10, np.nan, np.arange(N, dtype=float))
+series_end = pd.Series(data_end)
+
+# Series with NaN scattered throughout
+data_mixed = np.where(np.arange(N) % 7 == 0, np.nan, np.arange(N, dtype=float))
+series_mixed = pd.Series(data_mixed)
+
+# Warm-up
+for _ in range(20):
+    series_start.first_valid_index()
+    series_end.last_valid_index()
+    series_mixed.first_valid_index()
+    series_mixed.last_valid_index()
+
+iterations = 500
+start = time.perf_counter()
+for _ in range(iterations):
+    series_start.first_valid_index()
+    series_end.last_valid_index()
+    series_mixed.first_valid_index()
+    series_mixed.last_valid_index()
+total_ms = (time.perf_counter() - start) * 1000
+
+print(json.dumps({
+    "function": "first_last_valid_index",
+    "mean_ms": total_ms / iterations,
+    "iterations": iterations,
+    "total_ms": total_ms,
+}))
diff --git a/benchmarks/pandas/bench_string_array.py b/benchmarks/pandas/bench_string_array.py
new file mode 100644
index 00000000..fd9bcda2
--- /dev/null
+++ b/benchmarks/pandas/bench_string_array.py
@@ -0,0 +1,41 @@
+"""Benchmark: StringArray — nullable string extension array operations.
+N=100_000 elements with ~10% nulls using pandas StringDtype.
+Tests: from_sequence, upper, lower, strip, contains, len, fillna.
+"""
+import json
+import time
+import pandas as pd
+
+N = 100_000
+WARMUP = 3
+ITERATIONS = 50
+
+WORDS = ["hello", "world", "  foo  ", "bar", "baz", "  qux  ", "quux", "corge", "grault", "garply"]
+
+raw = [(None if i % 10 == 0 else WORDS[i % len(WORDS)]) for i in range(N)]
+
+
+def run():
+    a = pd.array(raw, dtype="string")
+    _ = a.str.upper()
+    _ = a.str.lower()
+    _ = a.str.strip()
+    _ = a.str.contains("oo", na=False)
+    _ = a.str.len()
+    _ = a.fillna("NA")
+
+
+for _ in range(WARMUP):
+    run()
+
+start = time.perf_counter()
+for _ in range(ITERATIONS):
+    run()
+total = (time.perf_counter() - start) * 1000
+
+print(json.dumps({
+    "function": "string_array",
+    "mean_ms": total / ITERATIONS,
+    "iterations": ITERATIONS,
+    "total_ms": total,
+}))
diff --git a/benchmarks/tsb/bench_boolean_array.ts b/benchmarks/tsb/bench_boolean_array.ts
new file mode 100644
index 00000000..9d00600e
--- /dev/null
+++ b/benchmarks/tsb/bench_boolean_array.ts
@@ -0,0 +1,46 @@
+/**
+ * Benchmark: BooleanArray — nullable boolean extension array operations.
+ * N=100_000 elements with ~10% nulls. Tests from/any/all/sum/and/or/not/fillna.
+ */
+import { arrays } from "../../src/index.js";
+
+const N = 100_000;
+const WARMUP = 5;
+const ITERATIONS = 50;
+
+// Build input with ~10% nulls (same pattern across TS and Python)
+const raw: (boolean | null)[] = Array.from({ length: N }, (_, i) =>
+  i % 10 === 0 ? null : i % 3 !== 0,
+);
+
+// Build a second array for bitwise ops
+const raw2: (boolean | null)[] = Array.from({ length: N }, (_, i) =>
+  i % 7 === 0 ? null : i % 2 === 0,
+);
+
+function run(): void {
+  const a = arrays.BooleanArray.from(raw);
+  const b = arrays.BooleanArray.from(raw2);
+  a.any();
+  a.all();
+  a.sum();
+  a.and(b);
+  a.or(b);
+  a.not();
+  a.fillna(false);
+}
+
+for (let i = 0; i < WARMUP; i++) run();
+
+const start = performance.now();
+for (let i = 0; i < ITERATIONS; i++) run();
+const total = performance.now() - start;
+
+console.log(
+  JSON.stringify({
+    function: "boolean_array",
+    mean_ms: total / ITERATIONS,
+    iterations: ITERATIONS,
+    total_ms: total,
+  }),
+);
diff --git a/benchmarks/tsb/bench_first_last_valid_index.ts b/benchmarks/tsb/bench_first_last_valid_index.ts
new file mode 100644
index 00000000..33d04869
--- /dev/null
+++ b/benchmarks/tsb/bench_first_last_valid_index.ts
@@ -0,0 +1,52 @@
+/**
+ * Benchmark: firstValidIndex / lastValidIndex
+ * Outputs JSON: {"function": "first_last_valid_index", "mean_ms": ..., "iterations": ..., "total_ms": ...}
+ */
+import { Series, firstValidIndex, lastValidIndex } from "../../src/index.ts";
+
+const N = 100_000;
+
+// Series where first valid is near the start (a few NaN/null at beginning)
+const dataStart = Float64Array.from({ length: N }, (_, i) =>
+  i < 10 ? NaN : i,
+);
+const seriesStart = new Series({ data: dataStart });
+
+// Series where last valid is near the end (a few NaN/null at the end)
+const dataEnd = Float64Array.from({ length: N }, (_, i) =>
+  i >= N - 10 ? NaN : i,
+);
+const seriesEnd = new Series({ data: dataEnd });
+
+// Series with NaN scattered throughout (worst-case scan)
+const dataMixed = Float64Array.from({ length: N }, (_, i) =>
+  i % 7 === 0 ? NaN : i,
+);
+const seriesMixed = new Series({ data: dataMixed });
+
+// Warm-up
+for (let w = 0; w < 20; w++) {
+  firstValidIndex(seriesStart);
+  lastValidIndex(seriesEnd);
+  firstValidIndex(seriesMixed);
+  lastValidIndex(seriesMixed);
+}
+
+const iterations = 500;
+const start = performance.now();
+for (let i = 0; i < iterations; i++) {
+  firstValidIndex(seriesStart);
+  lastValidIndex(seriesEnd);
+  firstValidIndex(seriesMixed);
+  lastValidIndex(seriesMixed);
+}
+const total_ms = performance.now() - start;
+
+console.log(
+  JSON.stringify({
+    function: "first_last_valid_index",
+    mean_ms: total_ms / iterations,
+    iterations,
+    total_ms,
+  }),
+);
diff --git a/benchmarks/tsb/bench_string_array.ts b/benchmarks/tsb/bench_string_array.ts
new file mode 100644
index 00000000..6902f524
--- /dev/null
+++ b/benchmarks/tsb/bench_string_array.ts
@@ -0,0 +1,40 @@
+/**
+ * Benchmark: StringArray — nullable string extension array operations.
+ * N=100_000 elements with ~10% nulls. Tests from/upper/lower/strip/contains/len/fillna.
+ */
+import { arrays } from "../../src/index.js";
+
+const N = 100_000;
+const WARMUP = 3;
+const ITERATIONS = 50;
+
+const WORDS = ["hello", "world", "  foo  ", "bar", "baz", "  qux  ", "quux", "corge", "grault", "garply"];
+
+const raw: (string | null)[] = Array.from({ length: N }, (_, i) =>
+  i % 10 === 0 ? null : WORDS[i % WORDS.length],
+);
+
+function run(): void {
+  const a = arrays.StringArray.from(raw);
+  a.upper();
+  a.lower();
+  a.strip();
+  a.contains("oo");
+  a.len();
+  a.fillna("NA");
+}
+
+for (let i = 0; i < WARMUP; i++) run();
+
+const start = performance.now();
+for (let i = 0; i < ITERATIONS; i++) run();
+const total = performance.now() - start;
+
+console.log(
+  JSON.stringify({
+    function: "string_array",
+    mean_ms: total / ITERATIONS,
+    iterations: ITERATIONS,
+    total_ms: total,
+  }),
+);