Electroplex emission based on poly(N-vinylcarbazole) (PVK) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) has been studied. A emission peak at 595 nm was observed in EL spectrum but not in PL spectra in the devices. The emission originates from the transition between the excited state of BCP and the ground state of PVK. Because of the increase of emission zone, the device of PVK: BCP blend exhibited stronger electroplex emission. The emission of electronplex was enhanced for both of PVK/BCP double layer device and PVK:BCP blend device, and it is stronger for blend devices. At higher drive voltage, only electroplex emission was observed in the blend device.