Electropolymerization of poly(5-amino-1-naphthol) onto different conducting substrates was studied in HCl, HClO4, PTSA (p-toluene sulfonic acid) and HCSA (camphorsulfonic acid) media. In situ UV-vis spectroelectrochemical studies have shown spectral changes that demonstrate that the oxidation process is accompanied by the formation of polaronic and bipolaronic structures due to the ejection of electrons from the polymeric matrix. Resonance Raman spectroscopy was used to follow structural changes that occur during the redox processes of the polymer and it allows us to infer the formation of imine groups and the possible 'ortho' coupling during electropolymerization.