Cucurbit[7]uril is a cyclic organic molecule consisting of seven glycoluril units linked by methylene bridges. It has a rigid barrel-like structure with two identical inlets at both ends to selectively encapsulate guest molecules of appropriate size, shape, and polarity. Cucurbit[7]uril is known for its high binding affinity for a variety of organic and inorganic guests, including drugs, amino acids, peptides, and metal ions. This property makes them promising candidates for various applications in areas such as drug delivery, catalysis, and sensing.