Activity coefficients at infinite dilution gamma(infinity)(i) of solutes such as alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C-1-C-6 alcohols, esters, and aldehydes in the ionic liquids trimethyl-butylammonium bis(trifluoromethylsulfonyl) imide [Me3BuN][NTf2] have been determined by gas chromatography using the ionic liquids as stationary phase. The measurements were carried out at different temperatures between 302 K and 393 K. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution H-i(E,infinity) of the solutes in the ionic liquids have been derived. Vapor-liquid equilibria (VLE) of binary mixtures containing methanol, ethanol, and propan-1-ol in [Me3BuN][NTf2] were studied by using a static method. VLE measurements were carried out covering the whole concentration range at four different temperatures between 298.15 K and 313.15 K. Activity coefficients gamma i of solutes in the ionic liquid and their osmotic coefficients phi(i) in the [Me3BuN][NTf2] have been determined from the VLE data and are described formally by using the NRTL equation. gamma(infinity)(i) and H-i(E,infinity) for methanol, ethanol, and propan-1-ol in [Me3BuN][NTf2] are derived from the both the GC and the static method.