Simple, economical, and toxic-solvent-free one-pot separation of tea components, such as catechin and tannic acids, has been demonstrated using the novel pore-engineered nanocarbon, carbon nanocage (CNC), with regularly arranged cage-type mesopores. The CNC materials possess larger specific surface areas and pore volumes than conventional mesoporous carbon, CMK-3, and also exhibit excellent adsorption capacities for a typical dye (Alizarin Yellow) and tea components (catechin and tannic acids) relative to activated carbon, CMK-3, and mesoporous silica SBA-15. Competitive adsorption of catechin and tannic acid to the CNC material results in highly selective adsorption of tannic acid (ca. 95%) using a very simple one-pot process.