The standard (p degrees = 0.1 MPa) molar energies of combustion in oxygen of 2-thiophenecarbonitrile, 3-thiophenecarbonitrile, 2-thiopheneacetonitrile, 3-thiopheneacetonitrile, and 3-methyl-2-thiophenecarbonitrile were measured, at T = 298.15 K, by rotating-bomb calorimetry. The standard molar enthalpies of vaporization of these compounds at T = 298.15 K were determined using high temperature Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the title compounds in their crystalline and gaseous phases, respectively.