The asymmetric unit of the title compound, C28H32N42+·2Cl ·2H2O, contains half of a 3,3′-[1,4-phenylenebis(methylene)]bis(1-propylbenzimidazolium) cation, one chloride anion and one water molecule. The complete cation is generated by a crystallographic inversion center. The central benzene ring forms a dihedral angle of 66.06 (11)° with its adjacent benzimidazolium ring system. In the crystal, the cations, anions and water molecules are linked by O—H...Cl, C—H...O and C—H...Cl hydrogen bonds into a three-dimensional network. The crystal packing is further stabilized by π–π interactions, with centroid–centroid distances of 3.5561 (15) and 3.6708 (15) .
