Abstract: By dehydration of fumaric dihydrazide and benzoic acid as well as substituted benzoic acids respectively, in polyphosphoric acid, trans-l,2-bis ( 2′-(5′-phenyl-oxadiazol-1′,3′,4′-yl))ethylene and twenty of its derivatives with substituents on 5′-phenyl groups were synthesized, of which, the melting points, infrared spectra, ultraviolet spectra, fluorescence emission spectra, laser conversion efficiencies were determined. Their fluorescence quantum yields were obtained by the relative method as well.