A red-emitting fluorescent probe was developed for the sensitive and selective detection of H₂S. Upon treatment with H₂S, this probe exhibited a remarkable fluorescence enhancement (10 fold) with a large Stokes shift (125 nm). The detection limit of this probe was as low as 5.7 nM based on S/N = 3. The application of this probe in the detection of intracellular H₂S in living cells is successfully demonstrated.