3-(2-Hy-droxy-eth-yl)-1-(4-nitro-phen-yl)-1-benzo[]imidazol-3-ium bromide.

The cation of the title salt, CHNO ·Br, has a dihedral angle of 24.26 (6)° between its fused imidazole and 4-nitro-phenyl rings and the N-C-C-O torsion angle associated with the hy-droxy-ethyl substituent is 60.15 (17)°. In the crystal, the bromide ions act as double acceptors for hydrogen bonds from a hydroxyl group (O-H⋯Br) and a fused imidazolium moiety (C-H⋯Br). Additionally, C-H⋯O hydrogen bonds between the phenyl group and hydroxyl oxygen atom create a two-dimensional supra-molecular network extending diagonally in the crystallographic plane.