C5H7N2+.C7H5O3-, Mr = 232.2, orthorhombic, Pbca, a = 15.928(5), b = 11.830(5), c = 11.768(6) A, V = 2217(2) A3, Z = 8, Dm = 1.40, Dx = 1.391 g cm3, graphite-monochromated CuK alpha, lambda = 1.54178 A, mu = 8.04 cm-1, F(000) = 976, T = 295 K, final R = 0.050 for 1116 reflections. Both six-membered rings are planar. The cations and anions are linked together in chains along the [001] direction by N-H...O hydrogen bonds.