Used as a key building block in medicinal chemistry, particularly in the design of bioisosteres for phenyl and other aromatic rings. Its rigid, three-dimensional structure helps improve metabolic stability, solubility, and binding selectivity in drug molecules. Commonly employed in the development of CNS agents, kinase inhibitors, and PET tracers due to its favorable physicochemical properties and ability to modulate lipophilicity. Also utilized in fragment-based drug discovery to access novel chemical space.