Abstract 1, 4-Bis (triphenylphosphonium)-2-butene dichloride (BTPBDC) and 1, 4-bis (triphenyl phosphonium)-2-butene dithiocyanate (BTPBDT) were prepared and used as phase-transfer catalysts. Alkyl halides were converted efficiently to the corresponding alkyl thiocyanates under mild reaction conditions in water. No evidence for the formation of isothiocyanates as by-product of the reaction was observed.