The existence of cation-cation pi-pi stacking in ate 1.2,4-triazolium-dinitramide letramer and 1.2,4-triazolium-chloride letramer (two cations and two anions) is predicted base) on the structures optimized using second-order perturbation theory (MP2). In the most stable letramer structure of 1,2,4-triazolium-dinllramide, pi-pi stacking is formed with an interplane distance of -3.2 A and a parallel displacement of -1.4 A. In the most stable letramer structure of 1,2,4- triazolium-chloride. pi-pi stacking is formed with an interplane distance of -2.9 A and a parallel displacement of -1.0 A.