Dimethyl or diphenyl branched conjugated polycarbosilane oligomers in solutions, including poly [[1,4-bis(thiophenyl)buta-1,3-diyne]-alt-(dimethylsilane)1, poly[[1,4-bis(thiophenyl)buta-1,3-diyne]-alt-(diphenylsilane)I,poly [[1,4-bis(phenyl)buta-1,3-diyne ne]-alt-(dimethylsilane)1:, and poly[[1,4-bis(phenyl)buta-1,3-diyne]-alt silane)],were investigated by steady-state and:picosecond time-resolved spectroscopies to elucidate the effect of silicon-atom introduction into the pi-conjugated copolymer backbone and the substitution of the aromatic phenyl group on the silicon atom. The introduction of silicon atoms into pi-conjugated copolymer backbones induces slow decay emission components with lifetimes of about 450 ps in addition to pi-pi* local excited-state relaxations in the time-resolved fluorescence decay profiles. The diphenyls, which are branched in the silicon atoms, bring about broad, structureless emission bands in the low-frequency region of the steady-state fluorescence spectra. However, such broad bands do not occur in the case of dimethyl branched conjugated polycarbosilane oligomers. The time-resolved and solvent-dependent studies of these bands imply that the excited-state dynamics of diphenyl branched conjugated polycarbosilane oligomers can be related to an intramolecular charge-transfer dynamics through an inductive and (d-p) pi-conjugation effect between the pi-conjugated backbone and the branched phenyl ring.