Nitrogen-rich heterocycles are of great interest for the design of high-energy materials (HEMs) because they offer high density, positive heat of formation, superior detonation properties, and high thermal stability. Among the different types of nitrogen-rich heterocyclic azoles, 1,2,4-triazole provides a remarkable framework for the development of green energetic materials. The presence of functional groups, such as nitro, amino, and nitramino groups, affects the stability, thermal decomposition behavior, and energetic properties of HEMs. In the present study, we chose amino- and nitramino substituted 1,2,4-triazole and triazole containing both amino and carboxymethyl groups to compare their decomposition mechanisms. The decomposition pathways of 3-amino-1,2,4-triazole (1), 2,4-dihydro-3