Indium nitride films with microvillus-like nanostructure were fabricated using reactive ion plating with glancing-angle deposition technique. Electrochromic properties of the biomimetic indium nitride films were significantly improved due to expansion of surface area and the nanoporous feature of the microvillus shape. Amplitude of color change agreed with the theoretical value estimated for a simplified structure model with an assumption that all terminating atoms on the nanostructured indium nitride surface behave as active sites for the electrochromic reaction. (C) 2007 The Electrochemical Society.