Novel silicon-based copolymers show the UV-visible strong absorption bands around 347-387 nm. Their maximum photoluminescence (PL) wavelengths for silicon-based copolymers appeared around 420-480 run in the blue region. The present copolymers with a relatively short pi -conjugation length exhibit blue light-emitting diodes (LED) at the low operating voltages, due to the reduction of the LUMO level in luminescent polymers by introducing silicon atoms in luminescent polymers as well as the d-orbital participation of silicon atoms.