Abstract: In situ highly sensitive and accurate tumor sensing is of great significance for early cancer diagnosis and treatment. Fluorescence sensing of tumor biomarkers has attracted considerable attention due to its advantages of high sensitivity, operational simplicity, and capability for real-time in situ detection. Achieving high-quality tumor fluorescence imaging fundamentally depends on high-performance luminescent probes, and developing near-infrared-II (NIR-II) fluorescent probes with excellent tissue penetration depth and ultra?high response sensitivity provides a highly promising solution path for this. Herein, we reported a NIR-II fluorescent probe, TQT-Bpin, featuring aggregation-induced emission (AIE) characteristics. This probe can specifically respond to the hydrogen peroxide overexpressed in the tumor region, thereby in situ activating NIR-II fluorescence emission. It exhibits exceptional sensitivity and specificity, enabling real-time and responsive sensing and imaging of hydrogen peroxide in tumor areas, with advantages including an ultra-large Stokes shift(320 nm), excellent selectivity (detection limit down to 3.6 μmol/L), and superior stability. Such an NIR-II probe, which integrates deep tissue penetration, high sensitivity, and in situ responsiveness, provides a novel strategy for early diagnosis of tumors.

Key words: Fluorescent probes, NIR-II emission, Aggregation-induced emission, Hydrogen peroxide;In situactivating