1-(1H-Benzimidazol-1-ylmeth-yl)-3-[2-(di-isopropyl-amino)eth-yl]-1H-benzimid-azolium bromide 0.25-hydrate.

The title N-heterocyclic carbene derivative, C(23)H(30)N(5) (+)·Br(-)·0.25H(2)O, was synthesized using microwave heating and was characterized by (1)H and (13)C NMR spectroscopy and a single-crystal X-ray diffraction study. The structure of the title compound are stabilized by a network of intra- and inter-molecular C-H⋯Br hydrogen-bonding inter-actions. The crystal structure is further stabilized by π-π stacking inter-actions between benzene and imidazole fragment rings of parallel benzo[d]imidazole rings, with a separation of 3.486 (3) Å between the centroids of the benzene and imidazole rings. There is also an inter-molecular C-H⋯π inter-action in the crystal structure. The C-N bond lengths for the central benzimidazole ring are shorter than the average single C-N bond, thus showing varying degrees of double-bond character and indicating partial electron delocalization within the C-N-C-N-C fragment. The isopropyl group is disordered over two sites with occupancies of 0.792 (10) and 0.208 (10).