Chiral polysilylene copolymers derived from poly(di-n-pentylsilylene) (PDPS) with chiral (S)-2-methylbutyl side chains were prepared. Symmetrical bis[(S)-2-methylbutyl]silylene units (5-50%) as well as nonsymmetrical (S)-2-methylbutyl/n-pentylsilylene units (2-30%) were incorporated. The copolymers showed high optical activities and circular dichroism related to the sigma-sigma* transition in a cyclohexane solution. Increasing the degree of substitution with bulky chiral side chains resulted in narrowing of the absorption band and a blueshift of lambda(max) in solution. In the solid, copolymers with a low content of branched chiral units showed transitions to a columnarlike mesophase as known for PDPS; materials with a higher content exhibited no measurable thermal transitions.