The present review deals with the chemistry and thermolysis of NTO and plausible decomposition pathways have been described. The decomposition of 5-nitro-2, 4-dihydro-3H-1,2,4-triazole-3-one (NTO) induced by X-ray, UV, laser, photochemical irradiation has also been discussed. High-speed photographic studies of the impact responses of NTO are also included. The thermal decomposition of labelled NTO has also been described here. Methods of detection as well as safe disposal of NTO have also been mentioned.