A polymer based on tetrathionaphthalene (TTN) as a redox active molecular unit is presented. The sulfur-linked TTN polymer, in which TTN segments are covalently linked via thioether, exhibits reversible multiple redox responses and provides an observed capacity of at least 122 mAh g(-1) in an ethylene carbonate:diethyl carbonate (1:3 volume ratio) solution containing 1.0 M LiBF4 in the potential range from 3.2 to 4.4 V (vs Li/Li+) with good cyclability of the potential scan.