The activity coefficients at infinite dilution, gamma(infinity)(13), for 59 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, acetic acid, thiophene, ethers, ketones, esters, butanal 4, and acetonitrile in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate, [HMIM][TCB], were determined by gas-liquid chromatography at six temperatures over the range (318.15 to 368.15) K. The partial molar excess Gibbs free energies Delta G(1)(E,infinity) 1, enthalpies Delta H-1(E,infinity) 1, and entropies Delta S-1(E,infinity) 1 at infinite dilution were calculated from the experimental gamma(infinity)(13) values obtained over the temperature range. The gas-liquid partition coefficients, K-L were calculated for all solutes. The selectivities for different separation problems were calculated from gamma(infinity)(13) and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other tetracyanoborate-based ionic liquids. The densities of [HMIM][TCB] within the temperature range from 318.15 K to 368.15 K were measured. (C) 2011 Elsevier Ltd. All rights reserved.