A polystyrene-block-polysilane-block-polystyrene copoly-was synthesized by atom transfer radical polymerization (ATRP) to show a dilated smectic liquid crystal that has been theoretically well simulated for end-tethered rod-like particles. The Si-H end groups of the rigid rod-like helical polysilane synthesized by Wurtz-type condensation, with a narrow molecular weight distribution, were successfully functionalized with the ATRP initiator, followed by ATRP of the styrene monomer to give a coil-rod-coil triblock copolymer with a well-defined structure.