The structure and morphology of para-nitroaniline dispersed in various polymers such as polymethyl methacrylate, polyvinyl alcohol, polvinyl acetate and polyethylene oxide were investigated by X-ray diffraction and optical polarizing microscopy as a function of composition. At low concentrations the material showed little structure but at concentrations above 40% high crystallinity was observed. Although in all cases the crystal structure conformed to the monoclinic one with a = 12.33 Å, b = 6.07 Å, c = 8.59 Å and β = 91.45°, the intensities of different peaks especially the 101 and 012 reflections as well as the type of growth habit and morphology were strongly dependent on the polymer used.