Activity coefficients at infinite dilution (gamma(i)(infinity)) of alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C-1-C-7 alcohols, esters, and aldehydes in the ionic liquids 1-methyl-3-butylimidazolium bis(trifluoromethyl-sulfonyl) imide were determined by gas chromatography using the ionic liquid as stationary phase. The measurements were carried out at different temperatures between 302 K and 385 K. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution (H-i(epsilon 1 infinity)) of the solutes in the ionic liquids have been derived.