Three Mn(III) quadridentate Schiff base compounds with N, N'-(1, 1, 2, 2-tetramethylethylene)bis(5-chlorosalicylideneiminato) (5-Clsaltmen(2-)) were prepared and characterized: [Mn2(5-Clsaltmen)2(H2O2)2](ClO4)2 (1), [Mn-2(5-Clsaltmen)2(5-Clsal)(2)](ClO4)(2) (2; 5-Clsal = 5-chlorosalicylaidehydonato), and [NEt4](2)[Mn-2(5-Clsaltmen)(2)(MeOH)(2)][Fe(CN)(6)]ClO4.2MeOH (3). All compounds contain Mn(III) out-of-plane dimer units. The magnetic measurements revealed intra-dimer ferromagnetic exchange interaction between Mn(III) ions via phenolate oxygen, producing a S = 4 spin ground state.