2-(1H-Benzimidazol-2-yl)-4-nitro-phenol.

The title compound, C(13)H(9)N(3)O(3), was prepared by the reaction of 5-nitro-salicyl-aldehyde with 1,2-diamino-benzene in methanol. The whole mol-ecule is approximately planar, with a mean deviation from the plane defined by the non-H atoms of 0.0311 (4) Å, and with a dihedral angle between the benzene ring and the benzimidazole ring system of 1.1 (3)°. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, adjacent mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming centrosymmetric dimers.