Two nitrogen rich compounds, viz. triaminoguanidine azide and guanidine nitrate have been studied as mechanism of thermal decomposition. The decomposition mechanism as elucidated for both the nitrogen rich compounds has been examined, discussed and contrasted with an aim to find out the cause for the fast burning behavior of triaminoguanidine azide. Thermal analysis has been carried out using thermogravimetry, differential thermal analysis and differential scanning calorimetry. The hyphenated techniques, viz. thermogravimetry-Fourier transformer infrared spectroscopy (TG-MR) and pyrolyser-gas chromatography-mass spectroscopy (Py-GC-MS) have been utilized to find out the decomposition gases evolved at the various stages of decomposition. Results indicate that the breakage of N-NH2 bonds available in the molecular structure of triaminoguanidine azide and subsequent reactions are the major cause for the fast burning behavior of triaminoguanidine azide. (C) 2009 Elsevier B.V. All rights reserved.