Abstract: Infrared spectra for altogether 21 binary systems of methanol, ethanol, propanol, butanol, hexanol,octanol and decanol with three solvents of benzene, hexane and cyclohex-ane at 25, 35 and 45℃ were measured using FTIR Sx20 spectrometer. The spectra were separated by peak - resolution technique. Quantitative relationships between true concentrations of associated species and phenomenological concentrations of alcohols were then calculated by peak -heights and full widths at half -maximum. The RK equation was used to take into account physical interactions between molecules. Standard association constants and corresponding enthalpies of association of linear dimerization and cyclotetramerization for those alcohols were then obtained.