Recrystallization of the bismuth oxido cluster [Bi38O45(OMc)24(dmso)9]·2dmso·7H2O (A) (OMc = O2C4H5) from alcohols such as EtOH and iPrOH gave single crystals of the bismuth oxido clusters [Bi38O45(OMc)24(ROH)x(H2O)y] (1, R = Et, x = 13, y = 0; 2, R = iPr, x = 10, y = 2). Both compounds crystallize in the triclinic space group P1 ̅ and exhibit minor deviations in their cell parameters: 1, a = 17.0156(5) Å, b = 19.0048(5) Å, c = 20.2100(5) Å, α = 111.182(2) °, β = 111.475(2) °, γ = 100.716(2) °, V = 5275.7(3) Å3; 2, a = 17.2512(7) Å, b = 19.3712(7) Å, c = 19.6248(8) Å, α = 112.803(3) °, β = 105.969(3) °, γ = 100.183(3) °, V = 5507.08(40) Å3. ESI-MS studies show that the bismuth oxido clusters 1 and 2 are more easily desolvated as reported for the dmso-adduct A. Collision-induced dissociation (CID) experiments on the solvent free cluster ions reveal a new fragmentation path for the methacrylate ligands. They split into C3H4 fragments as the leaving group and a formate ion remains bound at the cluster core. Bismuth particles are formed after annealing of 1 at 300 °C whereas a composite consisting of Bi/β-Bi2O3/C was formed in the temperature range of 400-600 °C. Calcination of 1 at 300 °C and 400 °C provided the formation of an amorphous material containing bismuth and a composite composed of β-Bi2O3/Bi2O2CO3/Bi/C, respectively. At higher calcination temperatures, α-Bi2O3 was obtained. The decomposition products do not show any sulfate incorporation as observed for A.