Ag(+)-π interactions between Ag(+) ions and a water-soluble tetra-armed cyclen bearing aromatic side-arms (tetracesium 4,4',4'',4'''-((1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(methylene))tetrabenzoate, Cs4) are reported. The structure of the Ag(+) complex with Cs4 was examined using cold ESI-MS, and (1)H NMR and UV spectroscopies. It is found that when it forms Ag(+) complexes in water, Cs4 behaves like an insectivorous plant (Venus flytrap).