This thesis focuses on porous monolithic materials that are not in the forms of particles, fibers, or films. In particular, the synthetic strategy of porous monolithic materials via the sol-gel method accompanied by phase separation, which is characterized as the non-templating method for tailoring well-defined macropores, is described from the basics to actual synthesis. Porous materials are attracting more and more attention in various fields such as electronics, energy storage, catalysis, sensing, adsorbents, biomedical science, and separation science. To date, many efforts have been made...