3,3'-[1,2-Phenyl-enebis(methyl-ene)]bis-(1-octylbenzimidazolium) dibromide monohydrate.

In the title hydrated mol-ecular salt, C(38)H(52)N(4) (2+)·2Br(-)·H(2)O, the central benzene ring of the dication makes dihedral angles of 89.47 (13) and 72.69 (12)° with the pendant benzimidazol-3-ium rings. The conformations of the octyl side chains are completely different. In the crystal, the components are linked by O-H⋯Br, C-H⋯Br and C-H⋯O hydrogen bonds into a two-dimensional network lying parallel to the ac plane. Aromatic π-π stacking inter-actions are also observed [shortest centroid-to-centroid separation = 3.5047 (16) Å].