Ultra-thin WO3 nanorods (NRs) embedded polyaniline (PANI) composite thin films were synthesized by embedding WO3 NRs into polyaniline using a surface-initiated-polymerization method, followed by spin-coating deposition. The ultra-thin WO3 NRs with length of 60 nm and diameter of 4 nm were prepared by a solvothermal method. The nanofillers were well-dispersed in the polymer matrix. The nanocomposites were finally deposited onto ITO-coated glass via spin-coating technology. The electrochromic contrast, switching speed, and durability of the composite films were investigated in details. The composite film, being a dual electrochromic material, varied from purple to green, light yellow and finally dark blue. The switching speed (0.9 s) is much faster than the films only composed of WO3 NRs. The durability of the hybrid film was enhanced compared with neat WO3 NRs film. (C) 2013 Elsevier B.V. All rights reserved.