A new electrophilic monofluoromethylthiolating reagent N-fluoromethylthiophthalimide PhthSCH2F 1 was developed. Reagent 1 could be readily synthesized from easily available starting materials benzyl mercaptan and CH2FCl in three steps. N-fluoromethylthiophthalimide 1 is a powerful electrophilic monofluoromethylthiolating reagent that allows the monofluorome-thylthiolation of a wide range of nucleophiles including alkynes, aryl/vinyl boronic acids, electron-rich heteroarenes,-ketoesters and oxindoles, as well as thiols under mild conditions.