7-(2,4-Dinitrophenoxy)-4-methyl-2H-chromen-2-one (Compound 1) serves as a fluorescent probe for detecting hydrogen sulfide (H2S). It is characterized by a low detection limit (4×10^-6 mol/L), high selectivity, and great sensitivity. At a concentration of 150 µg/mL, it exhibits negligible cytotoxicity. The excitation wavelength is 331 nm, while in DMSO solvent, it emits at approximately 385 nm; upon addition of HS-, the fluorescence intensity significantly increases around 392 nm.