6-Nitro-benzimidazolium dihydrogen phosphate 6-nitro-benzimidazole solvate dihydrate.

In the crystal structure of the title compound, C(7)H(6)N(3)O(2) (+)·H(2)PO(4) (-)·C(7)H(5)N(3)O(2)·2H(2)O, the components are connected through O-H⋯O, N-H⋯O and O-H⋯N hydrogen-bonding inter-actions, forming a sheet-like structure parallel to (101). Adjacent sheets are further linked together by strong O-H⋯O hydrogen-bonds involving the dihydrogenphosphate groups. π-π stacking inter-actions between neighbouring aromatic constituents [centroid-centroid distance 3.653 (3) Å] help to consolidate the crystal packing.