We demonstrate here the size-selective inclusion of two types of dyes in different nanosized-channels. The resulting crystals are dichromic: they exhibit color-to-color transitions and different color intensities when exposed to polarized light. The arrays of donor and acceptor dyes assembled in parallel channels display energy transfer by nonradiative dipole-dipole coupling. The fluorescence resonance energy transfer (FRET) is confirmed by fluorescence life-time measurements in combination with photobleaching of the acceptor dye. Colorless cadmium-based crystals with the ligand, AdDB, were prepared as host matrix for the assembly of new materials for optical applications. Coordination of this ligand to bivalent cadmium cations resulted in the same coordination structure as recently found for other first row metals , but these new crystals are highly transparent (similar to the less stable manganese-based crystals) .