Abstract <p>High-energy-density materials are widely used in various application areas. Therefore, development of new such materials and study of their properties is an interesting and relevant task for scientists all over the world. This study presents a quantum chemical investigation of high-energy derivatives of tetracyclic compounds based on tris([1,2,3]triazolo)benzenes and 1,3,5-triazines. The primary objective is to determine their energetic properties, particularly the enthalpy of formation, using various computational methods, including density functional theory (DFT) with B3LYP/6-311+G(2d,p) and B3LYP/cc-pVTZ, the composite G4MP2 method, and its implementation in the NWChem software package. The enthalpy of formation was calculated using two approaches: atomization reactions and isodesmic reactions. The dependence of the enthalpy of formation on molecular structure and functional substituents was analyzed. The highest specific enthalpy of formation (per mass) was observed for derivatives containing nitramino and dinitramino groups, making them promising candidates for high-energy materials. IR spectra analysis confirmed characteristic vibrational modes of functional groups. Quantum chemical calculations were performed using the ‘‘Lomonosov-2’’ supercomputer and specialized computational software. The use of isodesmic reactions significantly reduced computation time while maintaining accuracy. The results contribute to the understanding of structure-property relationships in high-energy polycyclic compounds and provide valuable insights for the design of novel high-energy-density materials.</p>