Abstract A blue fluorescent 1,2,4-triazole derivative, DA-TAZ, was synthesized and exmined as an emitter layer in organic electroluminescent device. The device structure of glass substrate / indium-tin oxide / hole-transporting diamine layer / DA-TAZ layer / Mg:Ag was employed. The EL device exhibited bright blue light originating from the DA-TAZ emitter layer with a maximum luminance of 1200 cd/m2 at 14 volt.