A number of Nn-alkyltetrachlorophthalimides has been synthesized and Nn- butyltetrachlorophthalimide has been characterized by X-ray diffraction, FT-IR and NMR spectroscopy. Also B3LYP and DFT calculations have been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G (d, p) approach have been compared with the X-ray data. The screening constants for 13C and 1H atoms have ...