Photoluminescent characteristics of polysiloxane containing pendant mesogenic 4-cyanobiphenyl (CB) and its monomeric analogues were studied in THF solution. An excimer formation was observed, and the increase in CB content in polysiloxane induced the increase in the fluorescence intensity from the excimers. The fluorescence decays were analyzed by triexponential function, A high CB content induced small decay rates, indicating the decrease of nonradiational decay. Such suppression of the nonradiation decay in higher CB content was explained by a strong mesogenic interaction between CB groups in solution.