Thermochemical and thermophysical data on 24 organic nitrogen-containing compounds found in (or formed during the processing of) alternate fossil fuels are reported here. The data are combined to give ideal gas phase thermodynamic properties for 18 of the compounds. Statistical thermodynamic calculations for six of the compounds are given, and a comparison of statistically calculated values (including those previously published) and the calorimetric values obtained here is made. The results are used to determine the thermodynamic equilibrium conditions necessary for the removal of the nitrogen atom from the molecules. The report concludes with a discussion of future research in the area. This report is the first comprehensive compilation of thermochemical and thermophysical property data on organic nitrogen compounds present in the alternate fossil fuels. Removal of these compounds during precessing is necessary for the production of stable, environmentally acceptable products.