Spin coating technique is employed to produce thin phthalimide films using novel p-phthalimidobenzoic acid (FIBA) and N-(phthalimido)-p-aminobenzoic acid (FIABA) materials. Several spin speeds and various solution concentrations are chosen to monitor the thin film deposition process of these new materials. The optical properties are studied using UV-visible spectroscopy and spectroscopic ellipsometry methods. The absorption of the FIBA and FIABA films against the spin speed showed an exponential behavior. pi -> pi* transition is occurred. The thicknesses of thin films at 2000 rpm are obtained 15.86 nm for FIBA and 12.99 nm for FIABA using spectroscopic ellipsometry results.