In this work a combined theoretical and experimental study of 2-chloro-4-nitrobenzoic acid (CNBA) is reported using density functional theory (DFT) calculations as well as Raman and IR spectra have been recorded in the region 4000?400 cm?1 and 3500?100 cm?1, respectively. The optimized molecular geometry, normal mode wavenumbers, infrared intensities and Raman activities, corresponding vibrational assignments and intramolecular hydrogen bonds were investigated with the help of B3LYP method using 6-311G and cc-pVDZ basis sets. A detailed interpretation of the infrared and Raman spectra of CNBA is reported. The theoretical spectrograms for FT-IR and FT-Raman spectra of the title molecule have been constructed. The observed and calculated frequencies are found to be in good agreement stability of the molecule arising from hyper-conjugative interactions, leading to its bioactive charge delocalization have been analyzed using natural bond orbital (NBO) analysis__ampersandsignnbsp;