The first bi- and mononuclear rhodium(I) complexes [{Rh(μ-OSi(8)O(12)(i-Bu)(7))(cod)}(2)] (5), [Rh(cod)(PCy(3))(OSi(8)O(12)(i-Bu)(7))] (6) with a hindered hepta(iso-butyl)silsesquioxyl ligand bonded to the rhodium(I) center through Rh-O-Si bonds have been synthesized and their structures have been solved by spectroscopic methods and X-ray analysis. Their exemplary catalytic properties in silylative coupling of vinylsilanes with styrene are also presented.