The title compound, C(9)H(8)O(2)S(2), can be used as a chain transfer agent and may be used to control the behavior of polymerization reactions. O-H⋯O hydrogen bonds of moderate character link the mol-ecules into dimers. In the crystal, the dimers are linked into sheets by C-H⋯O inter-actions, forming R(4) (2)(12) and R(2) (2)(8) edge-fused rings running parallel to [101]. There are no inter-molecular inter-actions involving the S atoms.