The complex of 1,8-bis(dimethylamino)naphthalene (DMAN) with 1,2-dichloromaleic acid (ClMH(2)) has been examined by electron spectroscopy (ESCA), X-ray diffraction at 120 and 293 K, and C-13 and H-1 MAS NMR at 123 and 293 K. The complex contains two strong, asymmetric, ionic hydrogen bonds, [N-H ... N](+) and [O-H ... O](-). The asymmetry results from asymmetric intermolecular interactions of the oxygen atoms of the carboxylic groups. Well-resolved C-13 MAS NMR spectra of a DMAN salt show separate signals from protonated "almost symmetrical" carbons. The difference between the binding energies of core (and valence) electrons of the donor and acceptor atoms isa good measure of the strength of hydrogen bonds. The influence of hydrogen bonding on the binding energies of core electrons of the atoms of the ClMH(-) anion decreases with the increased distance from the [O-H ... O](-) hydrogen bond site.