The title compound, C(2)H(8)N(+)·C(6)H(4)NO(3) (-)·C(6)H(5)NO(3), was synthesized from dimethyl-amine and 4-nitro-phenol in an overall yield of 85%. The dihdral angles between the nphenyl rings and their attached nitro groups are 5.7 (6) and 2.5 (7)°. In the crystal, there are strong hydrogen bonds between the ammonium group and the nitro-phenol and nitro-phenolate O atoms, and between the nitr...