The electrochemical properties of phenothiazine dyes, thionine (TH+) and methylene blue (MB+), incorporated into Nafion and PSS films were studied. These dyes showed different electrochemical behaviour in Nafion film when compared to aqueous solution and PSS film. The observed electrochemical behaviour has been explained by the interaction of reduced TH+ and MB+ molecules with different regions of the Nafion film. In the PSS film, the incorporated dye molecules experienced purely a hydrophilic environment and showed electrochemical properties similar to that of aqueous solution. Further, the interaction of the reduced MB+ molecules with the hydrophobic fluorocarbon region of the Nafion film was studied by spectroelectrochemistry adding 2-propanol to the supporting electrolyte solution.