Organic rechargeable batteries have received significant research interest from the viewpoints of structural diversity and sustainability of electrode materials. We designed core structures of organic cathode materials for lithium-ion (Li-ion) batteries based on density functional theory (DFT) calculations, which indicated that six-membered cyclic 1,2-diketones serve as excellent core structures because of the high redox energy change resulting from favorable coordination of the oxygen atoms to Li and the aromaticity of the reduced form. Here, we show that the Li-ion battery composed of pyrene-4,5,9,10-tetraone (PYT), which has two six-membered cyclic 1,2-diketone units, bound to polymethacrylate exhibits remarkable charge-discharge properties with a high specific capacity of 231 mAh/g, excellent rechargeability (83% of the capacity retained after 500 cycles), and charge-discharge ability (90% of the capacity at 30 C as compared to 1 C) in the LiNTf2/tetraglyme ionic-liquid system.