X-Ray diffraction, IR and 1H NMR studies were performed on the 1:1 adduct of 1,8-bis(dimethylamino)naphthalene (DMAN) with 1,8-dihydroxy-2,4-dinitronaphthalene (DHDNN). The adduct crystallizes in the triclinic system, space group Pl̄, a = 9.911(2) Å, b = 11.212(2) Å, c = 11.194(2) Å, α = 68.95(2)°, β = 79.72(2)°, γ = 73.78(2)°, Z = 2. Both [NHN]+ and [OHO]− hydrogen bonds formed in the ion pairs are asymmetrical with lengths equal to 2.574(2) Å and 2.466(4) Å respectively. The [NHN]+ bridge shows a typical behaviour in the IR spectrum, i.e. a low-frequency absorption between 300 and 700 cm−1. The coupling of [OHO]− hydrogen bonds with the naphthalene π-electron system is so strong that no absorption related to the proton stretching vibrations can be detected in the high- and low-frequency regions. The 1H NMR chemical shifts for the [NHN]+ and [OHO]− bridge protons of 18.63 and 15.81 ppm respectively confirm the strong hydrogen bonds.