The standard (p degrees = 0.1 MPa) molar enthalpies of combustion of 5-nitroindole and 5-nitroindoline, both in the solid phase, were measured at T = 298.15 K by static bomb calorimetry. Further, the standard molar enthalpies of sublimation, at T = 298.15 K. of these two indole derivatives were determined by Knudsen effusion technique. The combustion calorimetry results together with those from the Knudsen effusion technique, were used to derive the standard molar enthalpies of formation, at T = 298.15 K, in the gaseous phase. [GRAPHICS] (c) 2008 Elsevier Ltd. All rights reserved.