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This study investigates energy transfer between N,N 0 -bis-(1-naphthyl)-N,N 0 -diphenyl-1,1-biphenyl-4-4 0 -diamine (NPB) host material and 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-8-yl) vinyl]-4H-pyran (DCM2) fluorescent dye in organic electroluminescent (OEL) devices to produce white-color emission. Bathocuproine (BCP) was applied as a hole-blocking layer (HBL) due to its significantly large HOMO, while tris-(8-hydroxy-quinoline) aluminum (Alq 3 ) was employed in the electron transport layer (ETL). Two OEL device structures were investigated, ITO/NPB:DCM2 (x%)/Alq 3 /Al, and ITO/NPB:DCM2 (y%)/BCP/Alq 3 /Al. In this study, doping DCM2 into the NPB host material could not yield red emission in the case of ITO/NPB:DCM2 (x%)/Alq 3 /Al structure device, even when the DCM2 doping concentration was increased from x ¼ 1% to 10%. However, when BCP was inserted between the NPB:DCM2 layer and the Alq 3 layer, the color turned when the concentration of DCM2 doped into NPB was changed.Consequently, the white OEL device with CIE coordinates (0.34,0.34) was observed for the device containing 1% DCM2 doping into NPB host material. r