Conjugated carbonyl compounds have received vast attention as cathode materials for developing green lithium-ion batteries (LIBs). However, their high dissolution and poor electronic conductivity in organic electrolyte restrict their further application. Herein, a self-polymerized nitro-substituted conjugated carbonyl compound (2,7-dianitropyrene-4,5,9,10-tetraone, PT-2NO2) is applied as high-performance cathode materials for LIBs. The PT-2NO2 exhibits a high reversible capacity of 153.9 mAh g-1 at 50 mA g-1 after 120 cycles, which is higher than that of other substituted compounds. Detailed characterization and theorical calculation have testified that PT-2NO2 is transformed into azo polymer through the irreversible reductive coupling reaction in the first discharge process, and then carbonyl and azo groups can reversibly react with Li ion in the following cycles. In addition, this azo polymer is also synthesized and applied as the electrode material, which shows similar electrochemical performance to the PT-2NO2 but with higher initial coulombic efficiency. Thus, this work provides a simple but effectively way to construct organic cathode materials with multi-redox sites for green and high-performance LIBs.