For example, one of the strategies, which is considered a basic technology, is to synthesise a compound with the desired precursor using surfactants/porous substrates. The second step can be calcination/heating or washing with acidic/basic reagents to remove some of the compounds, thereby generating a porous structure. In this context, hydro(solvo)thermal strategies enable the direct (single-step) synthesis of diverse porous materials, which is attractive in terms of cost. This method targets the chemistry of the metal alkoxides and alkyls to generate a porous hierarchy without the use of external templates . Table summarises some strategies based on conventional and unconventional hydro(solvo)thermal methods to obtain diverse porous materials.