Triple-armed cyclens bearing three aromatic side-arms were prepared in three steps from (3R,5S)-3,5-dimethyl-1,4,7,10-tetraazacyclododecane-2,6-dione, and the Ag⁺-ion-induced ¹H NMR and UV-vis spectral changes and X-ray structures suggested that the aromatic side-arms cover the Ag⁺ incorporated into the ligand cavities like an insectivorous plant (Venus flytrap).