In this work, 2,2'-methylene-bis-(4,6-di-t-butylphenylene)phosphate lithium (NA03) was synthesized and its crystal structural characterization was obtained by single crystal X-ray diffusion. The crystal data showed geometrically the cell parameter of NA03 matched with isotactic polypropylene (iPP), the a cell dimension was about two times to the value of cell edge of (010)iPP. The disregistry was 2.89%, which was under the upper limit between the lattice matching spacing of host and guest crystals. Then NA03 was proved to be a highly effective nucleating agent for iPP through studying crystallization behaviors, crystallization morphologies, and mechanical properties of iPP nucleated with NA03. The outstanding nucleation efficiency could be attributed to the lattice matching between nucleating agent and iPP. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012