Redox-active organic materials have shown great potential as electrodes in lithium-ion batteries (LIBs). However, most of them showed a low discharge potential. We report a thianthrene-based small molecule (BDBDT), which could be facilely synthesized, as high-potential cathodes. The BDBDT cathode exhibited good electrochemical performance with a discharge plateau at 3.9 V (vs. Li/Li⁺), and a discharge capacity of 63 mAh g^-1 after 100 cycles at 500 mA g^-1 (~10C). Our results demonstrate that thianthrene-based molecules are promising for the development of high-potential organic electrodes towards rechargeable batteries with high energy and power density.