New data were determined by comparative ebulliometry for infinite-dilution activity coefficients of the following systems : chloroform/methanol, chloroform/acetonitrile, chloroform/tetrahydrofuran, chloroform/methyl acetate, chloroform/diethylamine and diethylamine/n-hexane, at both the upper and lower concentration limits and at two different temperatures. The measured infinite-dilution activity coefficients were compared with the predicted values obtained with the MOSCED (Modified Separation of Cohesive Energy Density) and UNIFAC models. For the UNIFAC model the predictions were made using group-interactions from the VLE parameter Tables. The differences between experimental and calculated infinite-dilution activity coefficients show that both methods predict fairly well the majority of the experimental data. The data obtained were used to estimate UNIFAC interaction parameters for the groups CCl3/CH3OH, CCl3/CCN, CCl3/CH2O, CCl3/CCOO, CCl3/CNH and CH2/CNH, which are not available in the infinite-dilution specific Parameter Table. These parameters were used to predict VLE data for systems containing the same groups, and a comparison between experimental and predicted values is presented.