The oxidation reaction of dithia[3.3]metacyclophane-containing pi-conjugated polymer (3) was performed by the treatment with m-chloroperbenzoic acid (m-CPBA). The reaction proceeded smoothly to obtain the corresponding oxidized polymer (4), and all sulfur atoms of the dithia[3.3]metacyclophane unit were converted to the sulfone group according to the H-1, C-13 NMR, and IR spectra. The rapid syn-[anti]-syn interconversion of the oxidized dithia[3.3]metacyclophane moieties in polymer (4) and dithia[3.3]metacyclophane moieties in polymer (3) occured in solution at room temperature. Polymer (4) exhibited a blue emission in the same region as polymer (3).