The first magnesium, manganese, cobalt, nickel, and zinc borosulfates were synthesized employing solvothermal conditions starting from the superacid H[B-(HSO4)(4)] and the respective metal powders (Mg, Ni, Zn) or oxides (MnO2, CoO). alpha-M-4[B2O(SO4)(6)] (M = Mg, Mn, Co, Ni, Zn) crystallize isotypically in a new structure type in P (3) over bar (No. 147) with Z = 1, a = 793.59(4)-810.86(9) pm, and c = 743.98(4)-775.09(9) pm. The oligomeric anion comprises unprecedented dimeric open-branched quadruple tetrahedra {oB, 4t}[B2O(SO4)(6)](8-), which are connected via M2O9 dimers to give a three-dimensional network. Upon mild heating, we observed a phase change from alpha-Mg-4[B2O(SO4)(6)] to beta-Mg-4[B2O(SO4)(6)], yielding a further new structure type in P (3) over bar (No. 147) with Z = 3, a = 1391.96(6) pm, and c = 748.54(3) pm. The reaction of MgB2 with SO3 yields Mg[B-2(SO4)(4)] crystallizing in C2/c with Z = 4, a = 1744.28(10) pm, b = 531.45(3) pm, c = 1429.06(8) pm, and beta = 126.323(2)degrees showing phyllosilicate topology. UV/vis spectroscopy on alpha-TM4[B2O(SO4)(6)] (TM = Co, Ni) confirms the valence state of the TM and reveals that borosulfates are weakly coordinating host structures. Structure relationships between the presented crystal structures and similar borophosphates are shown. The results of vibrational spectroscopy as well as magnetic and thermal measurement investigations are discussed.