Organic soluble, oleic acid capped TiO2 nano-rod was well-mixed with the electrochromic polymer: Poly-(4,4-dioctylcyclopenta[2,1-b:3,4-b']-dithiophene (PDOCPDT) to form TiO2/PDOCPDT nanocompsoite. TiO2/PDOCPDT film showed high electrochemical stability and its coloration efficiency is 1.5 times of that for pure PDOCPDT. The function of TiO2 nano-rods can be regarded as a dispersion agent. PDOCPDT chains in TiO2/PDOCPDT may have a less aggregated structure and more open morphology, therefore has higher coloration efficiency. TiO2 may also act as electron transport or temporary electron storage centers, electrons can be transferred reversibly between PDOCPDT and TiO2 nano-rods. TiO2/PDOCPDT is well-soluble in CHCl3, large area thin films can be fabricated reproducibly simply by spin coating. (c) 2008 Wiley Periodicals, Inc.