Activity coefficients at infinite dilution of 14 organic solutes, alkanes, alkenes, and alkyl benzenes, in 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate, have been determined using gas-liquid chromatography over a temperature range of (303.15 to 363.15) K with the ionic liquid as the stationary phase. The partial molar excess enthalpies at infinite dilution were also determined for the solutes from the temperature dependence of the experimental activity values.