The variations of the structural orientations and optical bandgap values have been reported for the zinc phthalocyanine thin film coated on elevated substrate temperatures. The optical bandgap energy values are estimated from the Q band maximum. The increase in substrate temperature leads to a decrease in bandgap energy. The substrate temperature affects the orientation of the ZnPc molecule in the b axis and parallel to the substrate. The stacking axes were no longer parallel to the substrate but they inclined to the substrate due to elevation of the substrate temperature. (c) 2006 The Electrochemical Society.