| 2,8-dibromodibenzothiophene and 2,8-diformyldibenzhothiophene were synthesized from dibenzothiophene, and the synthetic conditions of 2,8-dibromodibenzothiophene was investigated. The influence of the Vilsmeier formylation reaction, the immediate Grignard reaction, the mediate Grignard reaction and the solvents on the synthesis of 2,8-diformyldibenzhothiophene was also investigated. It is found that the usage of butyllithium give good yield of 2,8-diformyldibenzhothiophene over -15℃with glacial and saline bath.Six C2v symmetricalπ-conjugated dibenzothiophene derivatives were synthesized by Witting reaction staring from 2,8-diformyldibenzhothiophene and two C2v symmetricalπ-conjugated dibenzothiophene derivatives were also synthesized by Heck Reaction staring from 2,8-dibromodibenzothiophene. The structures of these new compounds were determined by NMR, IR and MS methods. In addition, two 3,6-di(arylvinyl)-9-pentylcarbazole were synthesized by Witting reaction from 3,6-diformyl-9-pentylcarbazole according to the literature method and the influence of the solvents including chloroform, dichloromethane and tetrahydrofuran, was discussed. The photophysical properties of the C2v symmetricalπ-conjugated dibenzothiophene derivatives showed that the UV absorption ranged from 315 nm to 350 nm, the fluorescence emission range from 430 nm to 460 nm and the fluorescence quantum yields were in the range of 0.02～0.13. The results indicated that abnormal blue-shift in the UV-visible and fluorescence spectra of 2,8-di[2-(4-pyridyl)vinyl]dibenzothiophene was observed with the increasing of solvent polarity, and red-shifts were observed in UV-Visible spectra for another compounds. 2,8-di[2-(4-pyridyl)vinyl]dibenzothiophene and2,8-di[2-(4-nitrophenyl)vinyl]dibenzothiophene exhibited significant two photon absorption properties when excited with near IR laser light, indicating the potential applications in three dimensional laser microdevice fabrication.
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