Hyphenated methodology combined with thermal analysis and other analysis methods has been widely applied to the investigation of complex phenomena. Thermo Mass Photo is a thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS) instrument, which is one of the most widespread hyphenated systems, and a main product in the lineup of Rigaku’s evolved gas analytical systems. It consists of thermogravimetry-differential thermal analysis (TG-DTA) and photoionization mass spectrometry (PIMS) equipped with a unique skimmer-type interface. The simultaneous analysis of weight changes, endothermic or exothermic phenomena, and evolved gases can be applied to fundamental research, quality control, and development of new materials, etc. In this article, we have introduced several applications of the thermal decompositions of the polymers, minerals, and pharmaceuticals by Thermo Mass Photo.