Colorimetric/Fluorescent Dual‐Mode Sensing of Mercury Ions and Solid‐Phase On‐Site Fast Detection Using AIE‐Active Coumarin Derivative TXDS

Mercury ions present severe threats to both human health and the environment, making their detection of paramount importance. Here, we innovatively designed and synthesized coumarin derivative–based probe TXDS . By virtue of the robust interaction between the thiocarbonyl moiety of TXDS and Hg 2 ⁺, which effectively regulated intramolecular conformational locking, a superior aggregation‐induced emission (AIE) characteristic was successfully constructed. Probe TXDS , coupled with 100 nm Stokes shift, enabled highly sensitive and selective detection of Hg 2 ⁺ within the concentration range of 0.1–10 µM. In addition, probe TXDS demonstrated excellent solid–liquid dual‐mode detection capability for Hg 2 ⁺. Colorimetric sensing extended the detection range of Hg 2 ⁺ by 10‐fold, realizing the complementary advantages of the wide dynamic range of colorimetry and the high sensitivity of fluorimetry. Mechanochemical treatment, involving grinding TXDS with soil samples, achieved visual analysis of Hg 2 ⁺ within 20 s, highlighting the green, efficient, and cost‐effective nature of this approach. Moreover, the dye TXDO exhibited tunable piezochromic behavior, offering potential applications in forensic identification and information encryption.