DOTP (1,4,7,10-tetrakis(methylenephosphonic acid)-1,4,7,10-tetraazacycloclodecane) was reacted hydrothermally with MnCl2.2H(2)O and Ni(NO3)(2).6H(2)O resulting in two structurally different compounds. Mn[C3NH7(PO3H0.5)](4) crystallizes in the tetragonal space group P4/ncc, with a = 12.349(2) Angstrom, b = 12.349(2) Angstrom, c = 14.066(4) Angstrom, V = 2144.9(8) Angstrom(3), and Z = 4. Manganese atoms are tetrahedrally bonded by four phosphonate oxygen atoms from four equivalent ligands. All 12-membered macrocycles are connected in a "zigzag" manner by sharing manganese atoms and forming 22-membered cavities between each pair of two adjacent macrocycles. Ni[C3NH6(PO3H)](4)[Ni(H2O)(6)] crystallizes as an ion pair complex. Ni(1) is octahedrally coordinated to two pendent phosphonate oxygen atoms and four nitrogen atoms from the macrocyclic backbone. Ni(2) is surrounded by six coordinatedly bonded water molecules to form a hexaqua cation. The manganese complex shows ion exchange capability for Cs+.