The electrostability of the poly(3-methylthiophene) film prepared in nitrobenzene provided the opportunity to study its redox transformations in an extended anodic potential region with the exclusion of the overoxidation. From spectroelectrochemical results a capacitive region could be separated in the highly oxidized state of the layer which exhibited a large capacitance. This pattern-assumed to be related to charge separation/redistribution within the film at high potential field connected to solvent movements-is promising from the point of view of symmetric p-type/n-type superconductors.