2,4-Dihydroxybenzaldehyde 4-methylthiosemicarbazone

The approximately planar molecule of the title compound, C9H11N3O2S, is linked to adjacent molecules by O—H...S hydrogen bonds to form a zigzag chain. Adjacent chains are consolidated by N—H...O hydrogen bonds into a two-dimensional array. An intramolecular O—H...N link is also present.