Styrene derivatives reacted with diphenyl(trifluoromethane-sulfonyloxy)sulfonium trifluoromethanesulfonate (1) at low temperature to afford 2-arylethenyl(diphenyl)sulfonium triflates (2). Treatment of 2 with primary amines gave the corresponding 2-arylaziridines in high yields. One-pot synthesis of various aziridines was also. successfully carried out without isolation of the intermediate 2.