The asymmetric unit of the title compound, C(28)H(32)N(4) (2+)·2Br(-)·0.5H(2)O, contains one 3,3'-[1,2-phenyl-enebis(methyl-ene)]bis-(1-propyl-benzimidazolium) cation, two bromide anions and one half-mol-ecule of water. In the crystal, the whole 3,3'-[1,2-phen-yl-enebis(methyl-ene)]bis-(1-propyl-benzimidazolium) cation and one of the bromide anions are each disordered over two positions with site-occupancy ratios of 0.751 (6):0.249 (6) and 0.680 (8):0.320 (8). For the major component of the disordered cation, the central benzene ring forms dihedral angles of 83.6 (5) and 88.2 (4)° with its adjacent imidazole rings, while these angles for the minor component are 89.2 (15) and 84.9 (13)°. In the crystal, the cations and anions are linked by C-H⋯Br hydrogen bonds into dimers and then stacked along the c axis. The crystal packing is further stabilized by C-H⋯π and π-π inter-actions [shortest centroid-centroid distance = 3.646 (4) Å].