The optical properties of a thin film of the [Ru(bpy)3][NaCr(ox)3] network structure obtained by pulsed laser deposition are described. The luminescence shows the characteristic doublet of R lines at 14 400 cm–1 of the spin-forbidden ligand field transition 2E(t_2g³)-->4A2(t_2g³) of the [Cr(ox)3]3– chromophore. The resonant energy migration within the R1 line shows that the three-dimensional crystallographic structure is preserved during the coating process. The observation of the R lines of [Cr(bpy)3]3+ at 13 710 cm–1 indicates that a small fraction of Cr3+ ions migrate from the oxalate network to the tris-bipyridine cation site in the cavities of the network.