Quantum chemistry calculations have been performed by using Gaussian03 program to compute optimized geometry, harmonic vibrational frequency. Atomic charges at HF/6-31G(d,p), B3LYP/6-31G(d,p) and B3LYP/6-311++G(d,p) levels for 1-(2,6-Dichloro-4-nitrophenyl)-5-amino-4-cyanopyrazole (C 10 H 10 Cl 2 N 5 O 2 ) in the ground state are also calculated. The research shows that the presence of strong hydrogen bonding in the title compound. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. A detailed interpretation of the infrared spectra of the title compound is reported. The theoretical spectrograms for FT-IR spectra of the title compound have been constructed. In addition, the 13 C NMR and other molecular properties are further investigated.