The electrochromic properties of polypyrrole (PPy) synthesized with two different dyes, Remazol Black B (RB) and Dianix Red (DR), have been investigated concerning the influence of dye molecules on polymer structure ordering and electrochromic characteristics. The polymers have been electrochemically prepared. Structural characterization by X-ray diffraction (XRD) and Raman spectroscopy has shown the improvement of PPy chain ordering by dye molecules, which provides an easy mass transport at the interface, a better electronic charge transfer in the bulk, and resulting better electrochromic properties. (c) 2006 Elsevier B.V. All rights reserved.59112732