In this work, a fluorescent probe, 1, using naphthalimide-indole as a fluorophore and a 2,4-dinitrobenzene sulfonyl group as a recognition site for biothiols (GSH, Cys and Hcy) was developed. The probe can work in aqueous media with a rapid response time (within 4 min). In the detection of biothiols, the probe showed red emission (590 nm), low detection limits (8.97 × 10−9 M for GSH, 9.87 × 10−9 M for Cys, and 1.02 × 10−8 M for Hcy) and a 143 nm Stokes shift. Moreover, this probe exhibited potential practical applications for detecting biothiols in living cells.
