The reaction of [Rh-7(CO)(16)](3-) with BiCl3 under N-2 and at room temperature results in the formation of the new heterometallic [Bi@Rh-12(CO)(27)](3-) cluster in high yields. Further controlled addition of BiCl3 leads first to the formation of the dimeric [(Bi@Rh-12(CO)(26))(2)Bi](5-) and the closo-[Bi@Rh-14(CO)(27)Bi-2](3-) species in low yields, and finally, to the [Bi@Rh-17(CO)(33)Bi-2](4-) cluster. All clusters were spectroscopically characterized by IR and electrospray ionization mass spectrometry, and their molecular structures were fully determined by X-ray diffraction studies. Notably, they represent the first examples of Bi atoms interstitially lodged in metallic cages that, in this specific case, are all based on an icosahedral geometry. Moreover, [Bi@Rh-14(CO)(27)Bi-2](3-) forms an exceptional network of infinite zigzag chains in the solid state, thanks to intermolecular BiBi distances.