The electronic properties of polyhedral oligomeric silsesquioxanes (POSS) have recently been subjected to study. Although theoretical calculations have predicted that POSS can work as an acceptor for π-conjugated organic units, an effective reaction to incorporate aryl groups into a POSS backbone remains to be established. In this work, Rh-catalyzed direct arylation has been developed. Heptaisobutyl-POSS with a Si-H group was reacted with various aryl halides to form aryl-substitued POSSs.