In the title compound, C(8)H(12)N(+).C(8)HN(4)O(2)(-), the anion and cation lie on a crystallographic mirror plane and form planar ribbons via N-H...O [N...O = 2.933 (4) A, H...O = 2.01 A and N-H...O = 170 degrees] and N-H...N [N...N = 3.016 (5) A, H...N = 2.15 A and N-H...N = 169 degrees] hydrogen bonds. The ribbons are further linked via weak C-H...O and C-H...N hydrogen bonds. In adjacent planes, anions lie opposite cations; pi-pi interactions (separation a/2 = 3.520 A) exist between the anions and the cations, and stacks are formed, running along the a axis. The cations are disordered over two interpenetrating sites, with occupancies of 0.833 (5) and 0.167 (5).