(E)-1-(2-Hy-droxy-5-meth-oxy-benzyl-idene)thio-semicarbazide.

In the title mol­ecule, C9H11N3O2S, an intra­molecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked via pairs of N—H⋯S inter­actions, forming inversion dimers with R22(8) ring motifs. These dimers are further linked via N—H⋯S and N—H⋯O hydrogen bonds, forming a two-dimensional network lying parallel to (100). The crystal structure is further stabilized by inter­molecular π–π inter­actions [centroid–centroid distance = 3.7972 (9) A].