This work is devoted to the development of a process which allows, in only one step, the localization of organic coating chemically bonded to initially homogeneous substrates thanks to the coating process itself. Photoconductive properties of silicon are used to fulfil this goal. Light illumination through a mask, that activates the photoconductive properties of the substrate was used to promote the local electrografting of thin organic coatings. (C) 2008 Elsevier B.V. All rights reserved.