A new low band gap polyfluorene derivative, poly(2,7-bis-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-5yl)-fluoren-9-one) (PEFE), containing ethylenedioxythiophene as donor and fluorenone (FO) as an acceptor groups was electrochemically synthesized. Electrochemical polymerization of 2,7-bis-(2,3dihydro-thieno[3,4-b][1,4]dioxin-5-yl)-fluoren-9-one (EFE) was achieved in dichloromethane with 0.1 M tetrabutylammonium-hexafluorophosphate both via and potentiostatic methods. The polymer was characterized by cyclic voltammetry, UV-vis, FT-IR and NMR spectroscopic techniques. Spectroelectrochemical and electrochemical analysis revealed that the polymer film is both p- and n-dopable and can be successfully cycled and switched between its neutral and oxidized/reduced states. Furthermore, PEFE shows electrochromic behavior by a color change from brown to blue with a switching time of 1.65 s during oxidation with a high coloration efficiency (250 cm(2)/C). Fluorescence studies were also performed. (C) 2009 Elsevier Ltd. All rights reserved