The asymmetric unit of the title salt, C(12)H(24)N(+)·C(7)H(3)N(2)O(6) (-), contains two cations and two anions. In the crystal, the cations and anions are connected by N-H⋯O hydrogen bonds, forming a 12-membered ring with an R(4) (4)(12) graph-set motif. The center of this 12-membered ring coincides with an inversion centre. π-π stacking is observed between parallel benzene rings [centroid-centriod distance = 3.771 (2) Å].