The book focuses on the synthesis, purification, characterization and biological as well as crystallographic studies of crown ether containing peptides. The synthesis of peptide having crown ether ring of various sizes mainly 12-C-4 have been discussed. Difficulties encountered during the synthesis have also been mentioned. Apart from that the techniques used for the purification and characterization of these crown ether peptides have also been mentioned in detail.This book also describes the findings of crystallographic and theoretical studies which reveals some of the interesting structural and conformational aspects of DOPA derivatives. Apart from that the biological application explored using dipeptide is an interesting part of this book.