The standard molar enthalpy of formation Δf H m°(l) of the ionic liquid N-butyl-3-methylpyridinium dicyanamide has been determined at 298.15K by means of combustion calorimetry. Vaporization of the ionic liquid into the nitrogen stream in order to obtain vaporization enthalpy has been attempted, but no vaporization was achieved. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the G3MP2 theory. The combination of traditional combustion calorimetry with modern high-level quantum–chemical calculations allows estimation of the molar enthalpy of vaporization of the ionic liquid under study.