A multidentate hydrazone-type ligand (Z,Z)-bis(1-(pyridin-2-y1)-1-amino-methylidene) oxalohydrazide (H2L) was utilized in the synthesis of three new isomorphous tetranuclear complexes of the general formula [Ln(4)(HL)(4)(H2L)(2)(NO3)(4)] (NO3)(4)center dot 4CH(3)OH (Ln = Gd-III, 1, Tb-III, 2, Dy-III, 3) with the gridlike [2 X 2] topology. The analysis of the static magnetic data revealed weak anti-ferromagnetic interaction among lanthanide(III) atoms, o whereas dynamic magnetic data led to the observation of the single-molecule magnet behavior in zero static magnetic field for the Dy-4 compound 3 with U-eff = 42.6 K and tau(0) = 1.50 X 10(-5) s. The theoretical CASSCF calculations supported also the presence of the net toroidal magnetic moment, which classifies compound 3 also as a single-molecule toroic.