The synthesis of new and innovative macrocyclic amidinoureas from linear di-Boc-guanidino-alkylamines related to guazatine was accomplished. The macrocyclization reaction proceeds under mild conditions affording 11- to 16-membered rings with a new and previously undescribed structure in good yields. Enantiomericallypure macrocyclic amidinoureas were also synthesised. The strict correlation between