A novel Cu(II)-Mn(II) hexanuclear complex of formula [{MnCuL}(3)-(tma)](ClO4)(3)(.)8H(2)O [H2L = macrocyclic Robson proligand; H(3)tma = trimesic acid] has been obtained by connecting three hetero-binuclear [(CuMnL)-Mn-II-L-II](2+), cationic species through the trimesate anion. The complex exhibits a C-3 rotational symmetry, imposed by the geometry of the bridging ligand. The interaction within each Mn(II)Cu(II) pair is antiferromagnetic (J = -16.7 cm(-1)). A weak ferromagnetic coupling among the three S = 2 resulting spins through the tricarboxylato bridge leads to a S = 6 ground spin state, for which the spin polarization mechanism is responsible.