Reactions of Ph2SbCl3 with RSi(OH)(3) [where R = tert-Bu, cyclo-C6H11] and Ph2Si(OH)(2) in toluene in the presence of triethylamine as a base were performed. Single-crystal X-ray structural elucidation of the products revealed the formation of hexanuclear antimony(V) and mixed-valent antimony (III/V) oxo-hydroxo clusters built up of an incomplete cubane subunit. Interestingly, in all the reactions, at least one Sb-C bond cleavage has been observed, leading to the formation of novel cluster assemblies [(Ph2Sb)(4)(PhSb)(2)-(C4H9SiO3)(2)(O)(6)(OH)(2)] (1), [(Ph(2)Sh)(4)(PhSb)2(C6H11-SiO3)(2)(O)(6)(O-H)(2) 1 (2), [(Ph2Sb)(PhSb)(2)(Ph2SiO2)(2)(O)(3)-(OH)(2)]-Et3NH+ (3), and [(Ph2Sb)(4)(Sb)(2)(Ph2SiO2)(2)(O)(6)(OH)(2)] (4), respectively.