Cyclic voltammetry, chronoamperometry, UV-vis absorption spectroscopy, fluorescence spectroscopy, FTIR spectroscopy, and AFM techniques have been employed to investigate pyronin Y thin films formed on Au(111) substrates by electrochemical oxidation of pyronin Y monomer. The medium used in the electropolymerization was an anhydrous acetonitrile solution containing 0.1M TBAClO(4) as supporting electrolyte. Anodic electropolymerization potential (1450 mV) of pyronin Y has been obtained from cyclic voltammetry data. Solid-state electropolymerization of pyronin Y was performed by the potential-controlled electrolysis technique. Chronoamperometry studies indicate that the adsorption of pyronin Y takes place in an instantaneous three-dimensional nucleation and growth mechanism which is accompanied by random adsorption. UV-vis absorption and fluorescence spectra of the electrolysis solution as a function of electrodeposition time show the adsorption of insoluble pyronin Y films on Au electrode surface. FTIR-specular reflectance of a polymer coated Au electrode reveals that there is a possible C-C coupling in the formation of polymeric pyronin Y structure. A well ordered polymeric chain structure of pyronin Y on Au(111) has been observed from AFM data. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 94-100, 2009