(E)-3,4-Dihydroxy­benzaldehyde 4-methyl­thio­semicarbazone

The title compound, C(9)H(11)N(3)O(2)S, adopts an E configuration with respect to the C=N bond. The mol­ecule is approximately planar, with an r.m.s. deviation from the mean plane through all 15 non-H atoms of 0.152 Å; the dihedral angle between the benzene ring plane and the least-squares plane through the thio­semicarbazone unit is 12.48 (7)°. A weak intra­molecular N—H⋯N inter­action contributes to the planarity of the semicarbazone unit. Centrosymmetric pairs of O—H⋯O and N—H⋯S hydrogen bonds form chains along c, generating R (2) (2)(10) and R (2) (2)(8) ring motifs, respectively. In the crystal structure, these chains are further linked by inter­molecular O—H⋯S and C—H⋯O inter­actions, forming stacks down the c axis.