The π-conjugated structures of organic photovoltaic cells offer a viable answer to meet the growing need for renewable energy sources. This research investigates how the addition of benzocyclic groups such as benzofuran (BF), benzoxazole (BFz), indole (ID), benzimidazole (IDz), benzothiophene (BT), and benzothiazole (BTz) to porphyrin systems increases their electron donation potential for use in photovoltaic devices. The electronic, optical, and thermodynamic properties of seven molecular configurations (P, PID, PIDz, PBF, PBFz, PBT, and PBFz) were assessed through density functional theory (DFT) using the B3LYP/6-31G+(d,p) basis set. A steady reduction in the free energy points to greater stability, alongside changes in the dipole moment, demonstrates substantial charge polarization effects. An analysis of the HOMO-LUMO gaps demonstrates the enhanced electronic stability in PIDz, PBFz, PBT, and PBTz, which is vital for charge transfer optimization and reactivity improvements. PBFz and PBTz demonstrate promising DOS profiles that maximize the donor–acceptor overlap and electronic transitions, leading to a superior solar material performance. The N-H, C-H, and C=C vibrational modes play a key role in the charge delocalization and light absorption, which are essential to the photovoltaic performance. The optical measurements reveal a red shift, with λmax from P at 359.6 nm toward PID at 405.0 nm, while PBTz shows the maximum absorption levels, which demonstrates improved π → π* transitions, leading to enhanced light-harvesting capabilities. The transition density matrix, alongside exciton binding energy studies, reveals PBFz and PBTz as the top choices for solar cell technologies because of their superior charge separation abilities and excitonic features. The NBO analysis confirms PBFz and PBTz as the top materials for organic photovoltaics and nonlinear optics while providing a basis for ongoing optimization and device exploration.