Novel optical and electroluminescent characteristics of organic multiple-quantum-well (MQW) structure have been discussed comparing with MQW structure which consists of cyclopentadiene derivatives (PPCP) and aromatic diamine (TPD) and that of aluminum quinoline (Alq3) and aromatic diamine (TPD). Energy transfer of excitons has been found in both MQW structures of PPCP/TPD and Alq3/TPD systems. Unique electroluminescent characteristics with emission spectrum has been discussed in PPCP/TPD MQW system comparing with that of Alq3/TPD MQW system.