The paper reports the study of thermal stability and decomposition mechanisms of the newly synthesized phenyl series energetic molecule named 1-(2-methoxy,-3,5-dinitrophenyl)-1H-1,2,3-triazole (S-5) using time resolved pulsed photoacoustic (PA) pyro analysis technique. The thermal PA spectra of the compound was recorded using a Q-Switched Nd-YAG laser (532 nm, 7 ns, 10 Hz). TG-DTA technique was carried out for ascertaining the melting and decomposition temperature of the compound. The results of these two methods confirm that S-5 is thermally stable in the range of 30-350 degrees C. We have earlier reported that phenyl series 1,2,3-triazoles require high incident laser energy than that of benzyl series 1,2,3-triazoles [1]. However, our further investigation shows that the change in the position of principal functional groups affects the process of thermal decomposition. Also, the thermal stability of the compound is evaluated on the basis of quality factor (Q) of the PA cavity. Further, we have used GC-MS and FTIR techniques to identify some of the gaseous components released from the compounds. (C) 2016 Elsevier B.V. All rights reserved.