A new N-carboxamide compound (3) was synthesized by the reaction of dibenzoylaceticacid-$N$-carboxyethyla\-mide (1) and 3,4-dichloroaniline (2). The $N$-(3,4-dichlorophenyl)-3-oxo-3-phenyl-2-(phenylcarbonyl) propanamide (3) subsequently reacted with Cu salt to produce its Cu(II) complex compound (4). The compounds were characterized by analytical and spectral methods. In addition, X-ray diffraction was performed to characterize and obtain detailed information about the structure of 3. The fully optimized geometries of compounds 3 and 4 were calculated at different basis sets by using the Gaussian09 (G09) software to investigate their 3D geometries and electronic structures. Comparisons between the calculated and experimental data including molecular structures, fundamental vibrational modes, and electronic properties were made. The comparisons showed that the theoretical data were compatible with the corresponding experimental values of compounds 3 and 4.