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We have fabricated highly efficient blue emitting organic light emitting diodes (OLEDs) from a new host emitting material, 4,4’-Bis[carbazolyl-(9)]-stilbene (BCS), doped with pure carbazole (Cz). Polyethylene dioxythiophene (PEDOT) doped with polystyrenesulfonate (PSS) and with LiF/Al was used for the buffer between the anode, the indium-tin-oxide (ITO), and the emitting layer and for the cathode, respectively. In order to balance the charge injection in the emitting layer, we used N,N’-diphenyl-N,N’-bis(3-methylphenyl)1-1’-biphenyl 1-4,4’-diamine (TPD) and an oxadiazole derivative (t-Bu-PBD) as the hole and the electron transport materials, respectively. Our device turns on at 3.5 V and emits strong, pure blue light at 445 nm due to selective energy transfer from BCS to Cz with an external quantum efficiency of near 1.5 %. The power efficiency was 1.53 lm/W at an applied bias of 5.5 V with a luminance of 7750 cd/m2. The maximum luminance of 20200 cd/m2 was obtained at 7 V. The characteristics of the OLEDs containing the Cz-doped BCS were also compared with those from the OLEDs containing pure BCS.