AbstractFour dinucleating ligands based on sterically protected salicylaldimine units bridged by a variety of rigid groups have been prepared: 1,4‐bis[(3,5‐di‐tert‐butylsalicylidene)amino]benzene (PARA‐H2), 1,3‐bis[(3,5‐di‐tert‐butylsalicylidene)amino]benzene (META‐H2), 2,6‐bis[(3,5‐di‐tert‐butylsalicylidene)amino]pyridine (PYR‐H2) and 1,4‐bis[(3,5‐di‐tert‐butylsalicylidene)amino]‐2,3,5,6‐tetramethylbenzene (Me4PARA‐H2). Reactions with [(Me3Si)2N]2Mg·(thf)2 gave three new heteroleptic dinuclear magnesium complexes: PARA‐[MgN(SiMe3)2·thf]2, META‐[MgN(SiMe3)2·thf]2 and PYR‐[MgN(SiMe3)2·thf]2. The complex PARA‐[MgN(SiMe3)2·thf]2 was characterized by X‐ray diffraction. Reactions with [(Me3Si)2N]2Ca·(thf)2 gave mixtures of homoleptic and heteroleptic species. The homoleptic and heteroleptic calcium complexes [PARA‐Ca·(thf)2]2 and PARA‐[CaN(SiMe3)2·(thf)2]2 could be isolated and were structurally characterized. These complexes are not stable in solution. Attempted syntheses of Me4PARA‐[CaN(SiMe3)2·(thf)2]2 gave insoluble coordination polymers of Me4PARA‐Ca. Reactions with [(Me3Si)2N]2Zn gave precipitates of homoleptic dinuclear zinc complexes of which PYR‐Zn could be structurally characterized as a cyclic tetramer. The dinuclear magnesium complexes PARA‐[MgN(SiMe3)2·thf]2, META‐[MgN(SiMe3)2·thf]2 and PYR‐[MgN(SiMe3)2·thf]2 are neither active in the polymerization of epoxides nor in the copolymerization of epoxide/CO2 (cylohexene or propylene oxide) but initiate the polymerization of rac‐lactide. Yields of isolated polylactide strongly depend on the bridging unit and the solvent. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)