Liquid crystal owing to its anisotropic properties is an ideal intermedia for molecular action amplification, for example, chirality and isomerization. Dynamic control of cholesteric liquid crystal (CLCs) optical properties by photoresponsive switches and motors are particularly attractive because of their wide applications in reflected color changing and circularly polarized luminescence switching. When a molecular switch or motor is aligned in line with liquid crystals in a network, the mechanical isomerization or rotation can be amplified on a microscopic scale. The collective motion of molecular machines in a liquid crystal network is now able to induce oscillation, helical twisting, and bending motions which are crucial demonstrations artificially. In this thesis, we have introduced molecular switches and motors in liquid crystal, both dynamic control of LC cholesteric phase and microscopic motions of liquid crystal network have been achieved.