1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) is a macrocyclic chelating agent based on a 12-membered tetraaza ring with four pendant acetic acid arms. It is a white to off-white crystalline powder with the CAS number 60239-18-1. DOTA is known for its exceptional thermodynamic stability and kinetic inertness when forming complexes with various metal ions. The primary application of DOTA is in the field of medical imaging and radiotherapy, particularly for the chelation of lanthanide and actinide metal ions. It is a crucial precursor for synthesizing stable complexes with gadolinium (Gd³⁺) for use as contrast agents in magnetic resonance imaging (MRI), and with radioisotopes like yttrium-90 (⁹⁰Y) and lutetium-177 (¹⁷⁷Lu) for targeted radionuclide therapy in oncology. Its high binding affinity and selectivity make it indispensable in the development of radiopharmaceuticals and diagnostic agents. Beyond biomedical applications, DOTA and its derivatives are fundamental building blocks in supramolecular chemistry and materials science. They are used to create functionalized surfaces, molecular sensors, and separation materials due to their strong and specific metal-binding properties. This versatility underscores its role as a key synthetic intermediate for advanced functional materials.