Abstract: 1, 4-Bis(phenyl ethynyl) benzene and its bis substituted phenyl derivatives were synthesized. Their fluorescence quantum yields, laser energy transfer efficiencies, Infrared spectra, and Raman spectra have been measured. The majority of the Infrared bands and Raman bands of the title compounds have been assigned. Their structures and the effect of substituents on the both spectra have been discussed.

Key words: 1,4-Bis(substituted phenyl ethynyl)benzene, Fluorescence quantum yield, Laser energy transfer efficiency, Substituent effect