A chlorosulfonylation of vinylarenes using magnetic metal–organic framework (MOF) composite Cu-BTC@Fe3O4 (BTC = 1,3,5-benzenetricarboxylate) as the catalyst has been developed. This protocol features easily accessible starting materials, good functional group compatibility and simple recovery of the catalyst. The recovered catalyst could be reused for at least successive five runs with only a slight decrease in its catalytic activity.