A new organic compound, trans-2-[( A'-N, iV-dimethylamino ) styryl ] -5-dimesitylborylthiophene (abbreviated as DMASBT, 5) with dimesitylboryl, dimethylamino and styryl-thiophene as electron acceptor, electron donor and conjugate bridge respectively, was synthesized. Its crystal structure determined by X-ray diffraction method indicates that the B-C bond between B atom and it bridge is obviously shorter than those of between B atom and mesityl groups. This remarkably strengthened B-C bonding can be regarded as an evidence of additional p-7t conjugation between the B atom and n bridge. The photo-physical properties of 5 in various solvents were studied in details. With the increasing of the polarity of solvents, the emission band of 5 will be remarkably red-shifted, its quantum yield will be increased and the lifetime will be lengthened. 5 Shows strong nonlinear absorption in the NIR band (750 ~ 850 nm) in the laser experiments in THF solution. Especially when it was irradiated by a femto-second laser at 800 nm, a strong up-converted green fluorescence in THF was observed.

Key words: BORANE, up-converted fluosescence, THIOPHENE P, XRD, QUANTUM YIELD