Pulcherosine, a compound formed through the oxidative coupling of isodityrosine and tyrosine, features a biphenyl linkage that creates a 2,2'-dihydroxy-3-phenoxybiphenyl aromatic core. It functions as an intermediate in the transformation of isodityrosine into the tetramer di-isodityrosine. Additionally, Pulcherosine contributes to the formation of inter-polypeptide cross-links and/or extensive intra-polypeptide loops.