Abstract: The present invention provides novel receptor-binding cyclic peptides that advantageously display high receptor binding affinity and selectively. More particularly, the present invention provides integrin-binding cyclic peptides containing an integrin-binding motif such as an RGD motif, an aromatic amino acid such as a tyrosine residue, and a lysine residue having a pi-pi stacking moiety conjugated to its ?-amino group. Methods for identifying receptor-binding cyclic peptides and for using the cyclic peptides of the present invention for imaging a tumor, organ, or tissue and for treating cancer, inflammatory diseases, and autoimmune diseases are also provided.