The infinite dilution activity coefficient
(γ
i
∞) is often applied to characterize solvent–solute
interactions,
and, when accurately predicted, it can also serve as an early-stage
solvent selection tool. Ample data are available on the use of a variety
of models, which complicates decision making on which model to apply
and when to apply it. A comparative study was performed for eight
predictive models at 298.15 K, including the Hildebrand parameter
and the Hansen solubility parameters. Also, three group contribution
methods based on UNIFAC, COSMO-RS, the Abraham model, and the MOSCED
model were evaluated. Overall, the MOSCED model and the Abraham model
are most accurate for molecular solvents and ionic liquids, respectively,
with average relative deviations of 16.2% ± 1.35% and 65.1% ±
4.50%. Therefore, cautious decision making based on predicted γ
i
∞ in ionic liquids should always be done, because of the expected
significant deviations. A MOSCED model for ionic liquids could be
a potential approach for higher accuracy.