Polyimide cathode materials have enticed tremendous attention as alternatives to transition-metal electrodes owing to their large theoretical capacity, structural diversity, low cost, and rapid reaction kinetics. Conversely, such imide electrodes still face a severe challenge to achieve their energy storage applications satisfactorily due to the insufficient utilization of their redox-active sites originating from their low electronic conductivities. Herein, four functionalized polyimide composites have been fabricated by virtue of an in situ polycondensation reaction between a newly synthesized benzophenone–benzoquinone-based diamine and commercial dianhydrides in the presence of a conductive Super C45 material for application as cathode materials in Li-ion batteries. Such innovative integration of carbonyl groups of benzophenone, benzoquinone, and diimide rings with the Super C45 material not only creates a stable porous structure with abundant accessible redox-active sites but also guarantees fast electron/ion diffusion. Consequently, our targeted PMQP-SP cathode delivers high capacities of 143 mAhg⁻¹ at 0.2 C and 122 mAhg⁻¹ at 1 C and attains better rate capability besides ultra-stable cycling performance with 85% capacity retention over 500 cycles at 2 C. According to DFT calculations, the theoretical results are well consistent with the electrochemical performance of the synthesized composites. Generally, this work suggests an efficient strategy to design novel carbonyl-rich organic electrodes for next-generation green rechargeable batteries.