Polymorphism of non-linear optical material N-(4-nitrophenyl)-N-methylamino-acetonitrile (NPAN)

Two new crystalline polymorph modifications of the non-linear optical material N-(4-nitrophenyl)-N-methylamino-acetonitrile (NPAN) have been found and their structures have been established by X-ray analysis. The low-temperature structure of previously known polymorph of NPAN has also been determined. The comparative analysis of the packing of the NPAN molecules in these polymorphs provides the hints to the process of crystallization of the NPAN in different conditions.