Two enantiomeric pairs of new 3d-4f heterometallic clusters have been built from two enantiomer Schiff base derivatives, labeled as R-/S-H2L, in situ obtained from the condensation reactions with o-vanillin and R-/S-2-phenylglycinol. The formulas of the series clusters are [Mn(6)Ln(2)(mu(3)-OH)(4)(mu(4)-O)(Ac)(4)(H2O)(2)(R-L)(6)]center dot NO3 center dot OH (Ln = Dy (1R), Gd (2R)), [Mn(6)Ln(2)(mu(3)-OH)(4)(mu(4)-O)(Ac)(4)(H2O)(2)(S-L)(6)center dot NO3 center dot OH (Ln = Dy (1S), Gd (2S)), whose crystal structures and magnetic properties have been characterized. Structural analysis indicated that the above clusters consisted of a [Mn(6)Ln(2)] core, featuring a sandwich configuration. The results of magnetic measurements showed the presence of slow magnetic relaxation with the effective energy barrier of 14.85 K in two Dy derivatives under the condition of zero-dc field, while the significant magnetocaloric effect of Gd analogues was found in a wide temperature range.