Cycloparaphenylenes are aromatic macrocycles formed by the fusion of multiple benzene rings, with large hydrophobic cavities. They are used as supramolecular host materials because they are able to encapsulate large guest molecules and stabilize reaction intermediates. The rigid structure of cycloparaphenylenes provides stability and mechanical robustness to the host-guest complexes. Applications include catalysis, molecular recognition, and the development of new materials for electronics and photonics. In supramolecular chemistry, cycloparaphenylenes are used to create complex structures and functional supramolecular assemblies.