Characterisation and magnetic properties of new metal-radical complexes with bivalent Mn having a general formula {[Mn(hfac)(2)](m)(R)(n)} are given. In these complexes, the aminoxyl radicals have magnetic, triplet or quartet, ground state and form with Mn2+ heterospin structures. They show 1D, 2D and 3D behaviour depending on the crystal structure, chemical formula and molecular structure of radical. In the ordered state. the complexes form a ferrimagnetic structure due to a strong negative coupling between the radical and Mn spins. Magnetic anisotropy in some single crystals was studied. The 3D complex ([Mn(hfac)(2)](3)(3R(T))(2)) with a linear triradical can be described within a sublattice model of ferrimagnetism, one sublattice of which is formed by 1D chains, while the other consists of magnetically isolated Mn2+ ions. Its comparatively high T-C = 45 K is accounted for the large interchain exchange interaction (3.9 K) through the isolated Mn2+. Analysis of their paramagnetic properties shows that the higher energy excitations are related to the desintegration of the ferrimagnetic (1/2, 5/2, 1/2) linear trimer species, which can be isolated in all these compounds.