The preparation of an easily available, air/moisture insensitive electrophilic reagent, trifluoromethyl-substituted selenium ylide 1a, and its reactions with a variety of nucleophiles including β-ketoesters and silyl enol ethers, aryl/heteroaryl boronic acids, electron-rich heteroarenes and sulfinates were described. These results suggest that reagent 1a is a broadly applicable electrophilic trifluoromethylating reagent.