Cyclic peptides are peptide chains which contain a circular sequence of bonds. This can be through a connection between the amino and carboxyl ends of the peptide, or a connection between the amino end and a side chain, or the carboxyl end and a side chain,or two side chains or side-chain-to-side-chain cycles are most often synthesized via Cys-Cys or amide bond formation within a cyclic peptide. Many cyclic peptides have been discovered in nature and many others have been synthesized in the laboratory. Their length ranges from just two amino acid residues to hundreds. Cyclic peptides are increasingly employed as chemical tools in biology and drug discovery(e.g. peptide ligands with increased binding potency/selectivity and enhanced protease stability). They have gained a lot of interest as alternative sources of new drugs to traditional small molecules.