Simple operation, easily accessible starting materials, and short syntheses of the privileged scaffold thiochromane 1,1‐dioxide that widely exist in bioactive molecules was achieved by photocatalytic divergent cyclization of α‐allyl‐β‐ketosulfones with arylsulfonyl chlorides. Optimization and scope and limitations of this short and general pathway are described. The methodology provides an efficient strategy for the construction of a wide variety of thiochromane 1,1‐dioxide derivatives.