Emissive behaviors from the systems with the sizes of the order of visible wavelength are described. Control of electrically-pumped emission from thin-film electroluminescent devices by use of one-dimensional planer cavities is demonstrated. Photoluminescence behaviors from organic dielectric stacks with buried emissive centers prepared by vacuum-vapor deposition were examined. Photoluminescence from self-organized three-dimensional ordered arrays of polystyrene small particles with luminescent dyes is also studied. In both systems, inhibition of spontaneous emission due to photonic gaps were observed.