The double-decker sandwich complex Cp*Ir(2,3-Et(2)C(2)B(4)H(4)) (1a) was prepared via deprotonation of nido-2,3-Et(2)C(2)B(4)H(6) to its mono- or dianion and reaction with (Cp*IrCl2)(2) in THF and isolated as a colorless air-stable solid; the B(4)-chloro derivative 1b was also obtained. Decapitation of 1a and 1b with TMEDA afforded colorless nido-Cp*Ir(2,3-Et(2)C(2)B(3)H(5)) (2a) and its 4-chloro derivative 2b. Chlorination of 1a by Cl-2 or N-chlorosuccinimide gave the symmetrical species Cp*Ir(2,3-Et(2)C(2)B(4)H(3)-5-Cl) (1c), which was decapped to yield nido-Cp*Ir(2,3-Et(2)C(2)B(3)H(4)-5-Cl) (2C). The triple-decker complexes Cp*Ir(2,3-Et(2)C(2)B(3)B(2)-4[6]-Cl)IrCp* (3), an orange solid, and dark green Cp*Ir(2,3-Et(2)C(2)B(3)H(2)-4[6]-Cl)CoCp* (5) were prepared from 2a and nido-Cp*Co(2,3-Et(2)C(2)B(3)H(5)) (4a), respectively, by deprotonation and reaction with (Cp*IrCl2)(2) in THF. Reaction of the 2c(-) anion with Rh(MeCN)(3)-Cl-3 gave the dark green tetradecker complex [Cp*Ir(Et(2)C(2)B(3)H(2)-5-Cl)]2RhH (6). In an attempt to prepare a heterotrimetallic Co-Rh-Ir tetradecker sandwich, a three-way reaction involving the deprotonated anions derived from Cp*Co(2,3-Et(2)C(2)B(3)H(4)-5-Cl) (4b) and 2c with Rh(MeCN)(3)Cl-3 was conducted. The desired species Cp*Co(Et(2)C(2)B(3)H(2)Cl)RhH(Et(2)C(2)B(3)H(2)Cl)IrCp* (7) and the tetradeckers [Cp*Co(Et(2)C(2)B(3)H(2)Cl)]2RhH (8) and 6 were isolated in small quantities from the product mixture; many other apparent triple-decker and tetradecker products were detected via mass spectroscopy but were not characterized. All new compounds were isolated via column or plate chromatography and characterized via NMR, UV-visible, and mass spectroscopy and by X-ray crystal structure determinations of 1a and 3. Crystal data for 1a : space group C2/c; a = 28.890(5) Angstrom, b = 8.511(2) Angstrom, c = 15.698(4) Angstrom, beta = 107.61(2)degrees; Z = 8; R = 0.049 for 1404 independent reflections having I > 3 sigma(I). Crystal data for 3 : space group P2(1)/c; a = 11.775(4) Angstrom, b = 15.546(5) Angstrom, c = 15.500(5) Angstrom, beta = 103.16(3)degrees; Z = 4; R = 0.066 for 2635 independent reflections having I > 3 sigma(I).