Raman spectra of zinc(I1) and palladium(I1) octakis(8-decoxyethy1)porphyrins as thin solid films in a photoelectrochemical cell were compared to those of the same compounds in dilute CS2. Polaization measurements indicate that both porphyrins distort from D4h symmetry upon aggregation to the solid state. The orientation of the porphyrins within the thin films was examined by polarized Raman spectroscopy, indicating the planes of the porphyrin molecules are tilted about 35O from the substrate surface. X-ray diffraction studies of an ordered thin film of the zinc(I1) octakis(8-decoxyethy1)porphyrin indicate that the film is highly oriented and suggest an interporphyrin distance of ca. 4 A.