In the presence of additional ligands and polar solvents, the well-known μ3-oxo bridged triangular iron carboxylates easily reorganize and stabilize large complexes. We chose 3-formylsalicylic acid (H2L) in order to explore its coordinative ability, due to its multiple coordination donor groups like –COOH, –OH and –CHO Herein, new hexanuclear iron(III) clusters [Fe6O2(OH)2(L)2(H2O)2(O2CR)8]·MeCN (R = CMe3 (1); CHMe2 (2)), where L is the dianion of 3-formylsalicylic acid, are reported. Compounds 1 and 2 were prepared from the reaction of μ3-oxo trinuclear iron(III) precursors [Fe3(μ3- O)(H2O)3(O2CR)6](O2CR)·2HO2CR with 3-formylsalicylic acid in acetonitrile. Both structures comprise six Fe atoms in an almost planar arrangement that can be described as two oxo-centered triangular units [Fe3(μ3-O)]7+ joined together by two bridging hydroxide and two bridging carboxylate groups. The asymmetric units contain only half of an Fe6 molecule. All Fe atoms adopt distorted octahedral coordination geometries and are in the +3 oxidation state. The peripheral ligation of metal ions is completed by six carboxylate molecules and two aldehyde ligands which are in their monoanionic and dianionic forms, respectively. The two 3-formylsalicylic ligands act as tridentate, bridging Fe1 (Fe1’) and Fe2 (Fe2’) ions by the alkoxo groups within each [Fe3(μ3-O)]7+ unit. The oxigen atom of the formyl group is also coordinated, which was not reported so far for this ligand. All carboxylate groups adopt the bridging μ2-η1:η1 coordination mode: two of them join the edges of the triangular [Fe3(μ3-O)]7+ units and the remaining six link Fe atoms within the latters (Fig. 1). Detailed characterization of compounds 1 and 2 will be described in a forthcoming paper. Figure 1. The molecular structure of complex 2·CH3CN (left) and its [Fe6(μ3-O)2(μ-OH)2]12+ structural core (right). Color code: FeIII, olive green; O, red; C, grey. The hydrogen atoms, methyl groups and solvent molecules are omitted for clarity.