First, the polymer 9,10-di(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)anthracene-co-3,4-propylenedioxythiophene (A) was synthesized from 9,10-dibromoanthracene and tributyl(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)stannane via Stille Coupling reaction. Next, A was electrochemically copolymerized with 3,4-ethylenedioxythiophene to form poly(9,10-di(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)anthracene-co-3,4-propylenedioxythiophene) (P(A-co-EDOT)). The resulting copolymer's electrochemical, optical and electrochromic properties were then investigated. P(A-co-EDOT) was found to have the electrochromic property: It is dark navy in its neutral state and changes color to dark cyan in its oxidized state. Coloration efficiency of the copolymer was calculated as 142 cm(2)/C, with a 0.7 s switching time at 580 nm wavelength. (C) 2019 The Electrochemical Society.