The structure, growth, and morphology of composite films made by dispersing para nitroaniline (PNA) in poly(methyl methacrylate) (PMMA) was investigated with respect to different crystallization methods, composition, and application of electric field. The wide-angle X-ray diffraction scans showed large variations in intensity of different reflections, especially the Okl with composition and in the presence of an electric field. In addition, it also showed the occurrence of a new crystalline structure, possibly due to complex formation between PNA and PMMA. The presence of this complex was further confirmed by infrared spectroscopy and thermal analysis. In a certain range of composition (30 to 40% PNA), spherulitic morphology was observed, which otherwise consisted of needle-shaped crystals dispersed in amorphous matrix. The transparency of these films also depended strongly on the crystallization conditions, and highly transparent films could be obtained, even at high PNA content by application of electric field. These various results could be explained on the basis of the intermolecular interaction between PNA and PMMA, as well as preferential growth direction and orientation of the PNA crystals.