Six new cyclic tetranuclear complexes [{M(Cp*)(L)}(4)](4+) and [{Ru-II(L)(cymene)}(4)](4+) [Cp* = eta(5)-C5Me5, cymene = eta(6)-p-MeC6H4Pri; M = Rh-III and Ir-III; HL = 6-purinethione (H(2)put) and 2-amino-6-purinethione (H(2)aput)] were prepared in a self-assembly manner and characterized by NMR spectroscopy, electrospray ionization mass spectrometry, and X-ray crystal structure analysis, The two crystal structures of ({Rh(Cp*)(H(0.5)put)}(4)](CF3SO3)(2) and [{Ir(Cp*)-(Haput)}(4)](CF3SO3)(4) revealed that they have similar S-4 structures with an alternate chirality array of CACA. and all ligands adopt a mu-1kappaN(9):2kappa(2)S(6),N-7 coordination mode. The orientations of the four bridging ligands are alternately up and down, and they form a central square cavity. Interestingly, the cationic tetramers of the former are stacked up along the c axis, resulting in an infinite channel-like cavity. The driving force of this stacking is due to intermolecular double hydrogen bonds [N(1)-H...N(21) = 2.752(4) Angstrom] at both sides of the cavity. In the two Rh-III- and Ru-II-H(2)aput systems, it turned out that the dimeric species are dominantly formed in the reaction solutions but finally convert into the tetrameric species.