A new thin-film characterization setup was created based on the combination of a surface plasmon spectrometer with an electrochemical. cell operated under high pressure of up to 200 MPa, and at temperatures up to 120 degreesC. The examples given to document its performance include,photoisomerization studies with poly(methyl methacrylate) (PMMA) films partly derivatized with disperse red (DRI), as well as, a preliminary account of the electropolymerization of EDOT under pressure and the assessment of the redox properties of the resulting thin PEDOT films.