It was found that alkylating amino-nitropyridine was able to crystallize epitaxially in a matrix of the oriented polypropylene (PP) as its longest spacing crossed the periodical spacing between the oriented PP chains, that is, as its alkyl chain crossed the oriented PP chains. The degree of crystalline orientation of alkylating amino-nitropyridine in a drawn matrix of PP was somewhat lower than that of PP over all ranges of draw ratio, supporting the suggestion that its epitaxial growth progresses according to the degree of crystalline orientation of a drawn PP matrix. One of the possible models of this epitaxy structure, which matched its X-ray diffraction patterns well, has been deduced by using the crystal structure proposed in a previous paper.