In the presence of catalytic amount of cesiumhydroxide, the hydrothiolation of alkynylsulfides occurred at room temperature in DMF under nitrogen atmosphere to afford exclusive (Z)‐1,2‐diorganothio‐1‐alkene in excellent yields. It could provide a new and expedient way for the preparation of symmetrical and unsymmetrical (Z)‐1,2‐diorganolthio1‐1‐alkenes.