(E)-5-[(2-Hy-droxy-5-meth-oxy-benzyl-idene)amino]-1,3,4-thia-diazole-2(3H)-thione.

In the title thione-Schiff base compound, C(10)H(9)N(3)O(2)S(2), the dihedral angle between the benzene ring and the five-membered ring is 6.69 (8)°. An intra-molecular O-H⋯N hydrogen bond forms an S(2) (2)(6) ring. In the crystal, inversion dimers linked by pairs of N-H⋯S inter-actions occur, generating R(2) (2)(8) ring motifs. The crystal structure features a S⋯S contact [3.3776 (7) Å], which is significantly shorter than the sum of the van der Waals radii (3.7 Å). The crystal structure also features C-H⋯O and π-π inter-actions [centroid-centroid distances = 3.4636 (9)-3.808 (1) Å].