Hydrothermal reactions of manganese(II) salts with m-sulfophenylphosphonic acid (m-HO3S-Ph-PO3H2, H3L) and 1,10-phenanthroline (phen) led to six novel manganese(II) sulfonate-phosphonates, namely, [Mn-2(HL)(2)(phen)(4)][Mn-2(HL)(2)(phen)(4)(H2O)](2)center dot 6H(2)O (1), [Mn-4(L)(2)(phen)(8)(H2O)(2)][ClO4](2)center dot 3H(2)O (2), [Mn(phen)(H2O)(4)](2)[Mn-4(L)(4)(phen)(4)]center dot 10H(2)O (3), [Mn-6(L)(4)(phen)(8)(H2O)(2)]center dot 4H(2)O (4), [Mn-6(L)(4)(phen)(8)(H2O)(2)]center dot 24H(2)O (5), and [Mn-6(L)(4)(Phen)(6)(H2O)(4)]center dot 5H(2)O (6). The structure of 1 contains two types of dinuclear manganese(II) clusters, and 2-3 exhibit two types of tetranuclear manganese(II) cluster units. 4-5 feature two different types of isolated hexanuclear manganese(II) clusters, whereas the hexanuclear manganese(II) clusters in 6 are bridged by sulfonate-phosphonate ligands into a 1D chain. Magnetic property measurements indicate that there exist weak antiferromagnetic interactions between magnetic centers in all six compounds.