<p>This work examines the combined role of barium titanate (BaTiO₃) and reduced graphene oxide (rGO) as complementary nanofillers in polyaniline (PANI) composites, with emphasis on how interfacial structure controls dielectric response and thermal stability. Four compositions PANI, PANI/BaTiO₃, PANI/rGO, and PANI/BaTiO₃/rGO were fabricated via in situ oxidative interfacial polymerization, promoting intimate filler polymer contact and uniform hybrid integration. X-ray diffraction and electron microscopy confirm the formation of the composites and reveal filler induced changes in microstructural features and morphology consistent with enhanced interfacial coupling. Thermal analysis shows distinct but complementary effects: BaTiO₃ improves thermal robustness by delaying degradation, whereas rGO facilitates heat dissipation, resulting in the highest overall thermal stability for the ternary system. Dielectric measurements demonstrate that the PANI/BaTiO₃/rGO composite achieves the most favorable dielectric performance within the studied window, exhibiting elevated permittivity accompanied by controlled loss behavior. This response is attributed to Maxwell-Wagner-Sillars interfacial polarization and a distributed “micro-capacitor” effect created by the strong permittivity/conductivity mismatch among PANI, BaTiO₃, and rGO, while BaTiO₃ also acts as an insulating spacer that mitigates continuous leakage pathways. AC conductivity increases in rGO-containing samples and follows a mechanism consistent with localized hopping at lower frequencies and percolation assisted transport at higher frequencies and/or elevated temperatures. The results provide a structure property framework for designing thermally stable, dielectric enhanced PANI-based hybrids for dielectric layers, embedded capacitive elements, sensing, and EMI-shielding applications; however, quantitative energy density assessment requires breakdown strength and/or P-E measurements, which will be pursued in future work.</p>