Simple turn-on fluorescent probe for ultrafast and highly selective detection of hydrogen sulfide in aqueous solutions.

5H-Benzimidazo[1,2-c]quinazoline-6-thione (BI-QT), was synthesized as a benzimidazole-based probe to detect HS. BI-QT exhibits a fluorescent "turn-on" response in DMSO/HO (9:1, HEPES 10 mM, pH 7.4) upon the addition of HS.