A novel electrophilic-type trifluoromethylthiolation reagent, a trifluoromethanesulfonyl hypervalentiodoniumylide, was designed and reacted well with various nucleophiles to afford the desired CF3S-substituted products. In situ reduction of the trifluoromethanesulfonyl group to give the trifluoromethylthio group, which is the key step in this process, was realized in the presence of copper(I) chloride