Abstract: Organic electro luminescences （OEL） having a europium complex as an emitter are reported, and OEL devices with Tb green emission have been studied in our group as well. In this paper an Eu containing OEL color-changeable with applied voltage were reported. That is, the OEL colors were varied from red to green when the driving voltages were increased from 10V to 20V reversibly. The red emitter in the OEL devices is europium complex Eu（TTA）₃（TPPO）₂.