We report here the synthesis and characterization of a reactive liquid crystal (RLC) as a novel polymeric nucleating agent for the promotion of the nucleation efficiency of isotactic polypropylene (iPP). The RLC was synthesized by an in-situ photo-polymerization and was then grafted onto the molecular chain of iPP by the reactive blending. The phase transition and crystalline morphologies of RLC-iPP in the beta-nucleation were studied. It is found that the nucleation efficiency of beta-crystals of iPP can be increased to 42% with a very small amount of RLC grafting, which is much higher than the reported nucleation efficiency of polymeric nucleating agents up to now (23%). In addition, we found that the nucleation efficiency of beta-crystals is strongly related to the concentration of RLC for the reactive blending. The nucleation efficiency was decreased from 42% to about 17% with the increase of RLC concentration from 0.5% to 4%. We propose a possible nucleation mechanism for this interesting phenomenon. It is expected that this new beta-nucleation RLC will have potential industrial applications in the future. (C) 2013 Society of Plastics Engineers