The molecular association of chloroform with o-cresol compound was studied by quantum chemical calculations using different basis sets (6-31G (d,p), 6–31 + + G (d,p), and 6–311 + + G (d,p)) and their respective counterpoise corrected energies, geometries and frequencies were analyzed. Fourier transform infrared spectroscopy (FTIR) spectra (ATR mode) of chloroform, o-cresol, and the various mole fractions of chloroform: o-cresol (0.8:0.2, 0.6:0.4, 0.4:0.6, and 0.2:0.8) have been recorded at ambient temperature. The quantum chemical calculations of chloroform (monomer, dimer, and trimer) and o-cresol (monomer, dimer, and trimer) and the complex structures of 1:1 and 2:1 (o-cresol: chloroform) were optimized and analyzed using density functional theory (DFT). From the results of FTIR spectroscopy and DFT calculations, the following H-bonds were identified (o-cresol methyl and/or aryl) C-H…Cl (chloroform) and (chloroform) C-H…O and/or π (o-cresol). The trend of theoretical frequencies of the complex structures 2:2 and 2:3 exactly follow the experimental FTIR frequencies. The monomeric and dimeric associations of chloroform and dimeric, trimeric forms of o-cresol are identified.