1-{2-[2-(1H-Benzimidazol-1-yl)eth-oxy]eth-yl}-1H-benzimidazol-3-ium hexa-fluoro-phosphate.

In the title salt, C(18)H(19)N(4)O(+)·PF(6) (-), the dihedral angle between the benzimidazolium and benzimidazole ring systems is 16.24 (2)°. In the cation, a π-π inter-action is observed between the imidazolium ring and the benzene ring of the benzimidazole ring system [centroid-centroid distance = 3.5713 (11) Å]. The PF(6) (-) ion is disordered over two sites, with occupancies of 0.895 (2) and 0.105 (2). In the crystal structure, pairs of N-H⋯N hydrogen bonds link the cations, forming centrosymmetric dimers. The dimers are linked via π-π inter-actions [centroid-centroid distance = 3.5606 (11) Å]. In addition, C-H⋯F hydrogen bonds are observed.