Arysulfonylallenes (ArSO ₂ –CR ¹ =C=CR ² R ³ ), depending on their structure, react with iodine to give two types of products, diiodo alkenes ArSO ₂ –CHI–CI=CR ² R ³ , when R ¹ = H, or iodo dienes ArSO ₂ –CR ¹ =CI–C(Me)=CH ₂ , when R ¹ = Br, Ph and R ² = R ³ = Me, in yields of 55–98%. The plausible reaction mechanisms have been proposed.