The synthesis of dibenzothiophene derivative, i.e., 2,8-bis(trimethylsilyl)dibenzothiophene (3a) and dibenzothiophene-based poly(tetramethylsilarylenesiloxane) derivative (P1) was attained. In addition, 2,8-bis(trimethylsilyl)dibenzothiophene-5,5'-dioxide (3aO) and oxidized dibenzothiophene-based poly(tetramethylsilarylenesiloxane) derivative (P1O) were obtained by oxidation reaction of 3a and P1, respectively. The glass transition temperature was raised by the oxidation of the dibenzothiophene-based poly(tetramethylsilarylenesiloxane) derivative. The introduction of alkylsilyl groups onto dibenzothiophene derivatives induced no remarkable red shifts in the absorption as well as fluorescence spectra; however, the red shifts in the fluorescence spectra were observed by oxidation of dibenzothiophene derivatives.