Prospects are given how Raman spectroscopy can provide valuable insights into the understanding of processes that are operated at high pressures and high temperature. At high pressures and high temperatures Raman spectroscopy has been an efficient tool for the in situ analysis of mechanisms such as heat transfer, mass transfer, reaction, crystallization, decomposition, condensation, hydrolysis and others. Its future potential is discussed treating three specific example processes; (i) the extraction of valuable compounds from biomass, (ii) the conversion of biomass to platform chemicals and fuels and (iii) the decontamination of wastewaters containing organics. What is discussed for these three example processes can be transferred to other processes that do not have to take place at high temperature and high pressure. A brief introduction into applied Raman spectroscopy is provided in the context of these processes. Then it is described where in these processes the application of Raman spectroscopy can make substantial contributions to the understanding of the processes. Finally, some strategies are mentioned how Raman spectroscopy can be applied to high pressure and high temperature processes.