Photo-chemically tunable photonic band gap materials are prepared by infiltration of liquid crystal polymers having azobenzene groups into voids Of SiO2 inverse opal films. Linearly polarized (LP) light irradiation results in transformation from a random to an anisotropic molecular orientation of azobenzene side chains in the voids of the SiO2 inverse opal film, leading to the reversible and stable shift of the reflection peak to longer wavelength more than 15 nm. To improve switching properties, we use copolymers of azobenzene monomer and tolane monomer, which have higher birefringence, as infiltration materials into the voids. The azobenzene-tolane copolymers are found to show higher birefringence than azobenzene homopolymers by the LP light irradiation at higher temperature. Consequently, the reflection band of the SiO2 inverse opal film infiltrated with the azobenzene-tolane copolymer can be shifted to longer wavelength region more than 55 nm by the irradiation of LP light. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1981-1990, 2009