4-Amino-2-hy-droxy-benzohydrazide.

The asymmetric unit of the title compound, C(7)H(9)N(3)O(2), comprises two crystallographically independent mol-ecules (A and B). In each mol-ecule there is an intra-molecular O-H⋯O hydrogen bond making an S(6) ring motif. In the crystal, a pair of N-H⋯N hydrogen bonds link the two mol-ecules (A and B) into a dimer with an R(2) (2)(6) ring motif. The B mol-ecules are linked via pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R(2) (2)(10) ring motif. The mol-ecules are further linked via other N-H⋯O hydrogen bonds, forming undulating two-dimensional networks lying parallel to the bc plane. These networks are finally linked via N-H⋯O hydrogen bonds, forming a three-dimensional structure.