In this study, electrochromic properties of cobaltphthalocyanine (CoPc) immobilized on ITO electrode with electropolymerization were investigated (ITO/CoPc). CoPc substituted with electropolymerizable quinoline moieties was oxidatively electropolymerized on the working electrode during anodic potential scans with the help of polymerizable quinolone groups. In situ spectroelectrochemical measurements of CoPc in solution and in solid state showed that a metal based redox process of CoPc affected the optical spectrum more than the Pc based redox process as the existed bands shifted and new bands appeared, which showed the electrochromic feature of the complex. In order to investigate potential utility of the complex as electrochromic material, electrochromic properties of ITO/CoPc thin film were investigated in detail with various electrochemical, in-situ spectroelectrochemical and in-situ electrocolorimetric analysis methods. ITO/CoPc thin film showed reversible color change between cyan and purple colors. Short response times, high optic contrast and optical and coulombic stabilities of CoPc film indicate possible application of CoPc as anodic and cathodic coloring material in the display technologies. (C) 2014 Elsevier B.V. All rights reserved.