Strategies are discussed for the design of Ag+ selective macrocyclic molecules, together with the structures of the Ag+ complexes. One of the most useful and basic methods is to incorporate heteroatoms, such as nitrogens and sulfurs, and heterocycles into the macrocyclic framework. A side arm containing the heteroatom also enhances Ag+ selectivity tremendously. A sulfide chain outside or inside the macroring contributes to highly selective Ag+ binding. Soft alkenyl and alkynyl carbons arranged in a macrocyclic fashion bind Ag+ preferentially. Regulation of Ag+ binding by redox reactions and by metal ligation is also described.