The potential multireference character of the molecules was assessed using the T1 diagnostic test, which indicated single-reference wavefunctions for all cases, Table . For 7norbornene, a discrepancy was observed between CCSD and DFT results. To resolve this, the singlet and triplet structures of 7-norbornene were optimized at the CASSCF(4,4)/def2-TZVP level, and single-point CASPT2(4,4)/def2-TZVP computations were performed to determine the relative energies of the states. The triplet state was found to be 16 kcal•mol⁻¹ more stable than the singlet, indicating a dominant diradical character for 7-norbornene. All first-principles computations were performed using Gaussian 16 C01. The electronic structures of the molecules were analyzed using Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) methods . NBO analyses were conducted using NBO 3, implemented in Gaussian, while QTAIM analyses were performed using AIMAll (Version 19.10.12).