A method of wavelength tuning a composite material. The method includes the steps of: producing an ordered array of first constituents having a first refractive index embedded within a cross-linked metallopolymer network having a second refractive index different than the first refractive index, the ordered array of first constituents having a lattice spacing giving rise to Bragg diffraction when the composite material is illuminated; and switching the electronic configuration of the cross-linked metallopolymer network so that the cross-linked polymer network changes dimensions and modulates the lattice spacing of the ordered array of first constituents, which shifts the Bragg diffraction wavelength to a pre-selected wavelength.