We prepared novel photoreactive liquid crystalline (LC) polymer via polymer reaction. The cinnamic acid activated ester easily converted to amide by mixing with amine derivative and solubility of the polymer reduced due to hydrogen bonding. Upon exposure to linearly polarized ultraviolet light and subsequent annealing, the LC cinnamide exhibited axis selective photoreaction and following thermally amplification of molecular alignment. However, photoreactivity, LC stability and thermal amplification behavior of the cinnamide group were lower than that of original cinnamic acid group, suggesting that the lateral hydrogen bonding disturbs molecular reorientation behavior.