The asymmetric unit of the title compound, C(7)H(5)NS·0.5C(2)H(2)O(4), contains one benzothia-zole mol-ecule and half an oxalic acid mol-ecule, the complete mol-ecule being generated by inversion symmetry. The benzothia-zole mol-ecule is essentially planar, with a maximum deviation of 0.007 (1) Å. In the crystal, the benzothia-zole mol-ecules inter-act with the oxalic acid mol-ecules via O-H⋯N and C-H⋯O hydrogen bonds generating R(2) (2)(8) (× 2) and R(4) (4)(10) motifs, thereby forming supra-molecular ribbons along [101].