The chemistry of container molecules has developed extensively over the past two decades. Many container molecules such as calixarenes, resorcarenes, cyclodextrins, carcerands and glycourils have been invaluable in studying the fundamental principles of inclusion phenomena and consequently their use in separation science or drug delivery. Importantly, the area has attracted interest in the field of supramolecular chemistry because the properties of such host-guest compounds are often different from those of their constituent components. By adjusting the size and form of the binding cavity it is often possible to complex co-ligands in unusual coordination modes, to activate and transform small molecules, or to stabilize reactive intermediates. One subclass is the metallated container molecules, in which metal ions and clusters are used as both a point of recognition and to give the container a well-defined structure.Fig.1. Conformation type A-“partial cone” and B -“cone”. Fig.2. Crystal structure of complex 1. Interestingly, the macrocycles can adopt two different conformations A and B (Fig.1), which are reminiscent of the “partial cone” and “cone” conformations of the calixarenes. A detailed comparison of the individual structures has shown that the conformation of the amino thiophenolates (L)2− is coupled to the size of the coligand L′ and the metal ion radii. For the complexes of the 3d elements the type A conformation is only seen for small monoatomic bridging ligands such as L′ = OH‾ and Cl‾. For large monoatomic coligands (such as SH‾) or a multiatom bridging ligand (such as OAc‾) the bowl-shaped conformation B is assumed, the driving force being the more regular octahedral coordination environments about the MII ions. In view of the increasing interest in the targeted assembly of molecular-based magnetic materials using highspin molecules of higher nuclearity, it was of interest to prepare tetranuclear complexes by lin-king pairs of dinuclear [NiII 2(L)] entities via polydentate bridging ligands. Several such complexes were reported, and the ability of the bridging ligands to mediate long-range magnetic exchange interactions between the dinuclear subunits was examined. The tetranuclear nickel(II) complexes [{NiII 2(L)}2(acetylenedicarboxylate)][BPh4]2 (1), [{NiII 2(L)}2(terephthalate)][BPh4]2 (2), [{NiII 2(L)}2(isophthalate)][BPh4]2 (3), and [{NiII 2(L)}2(ferrocene-1,1′-dicarboxylate)][BPh4]2 (4) have been synthesized and characterized by UV/Vis-, IR spectroscopy, and X-ray crystallography. All dicarboxylates act as a quadridentate bridging ligands joining two bioctahedral [Ni2(L)]2+ units via μ1,3-bridging carboxylate functions to generate discrete [{NiII 2 (L)}2 (dicarboxylate)]2+ dications with a central LNi2(O2C–R–CO2)Ni2L core (Fig. 2). The structures differ mainly in the distance between the center of the Ni···Ni axes of the isostructural [Ni2(L)]2+ units (8.841(1)Å in 1, 10.712(1)Å in 2, 9.561(1)Å in 3, and 10.749Å in 4) and the tilting angle between the two Ni2O2 planes (86.3o in 1, 58.2o in 2, 20.9o in 3, and 33.1o in 4). Magnetic susceptibility measurements on the complexes over the temperature range 2.0–295 K reveal the presence of weak ferromagnetic exchange interactions between the NiII ions within the dinuclear subunits with values for the magnetic exchange constant J1 of 23.1(5), 18.1(5), 14.2(5), and 22.0(5)cm−1 for 1, 2, 3, and 4, respecti vely (H = −2JS1S2). The magnitude of the exchange interaction J2 across the dicarboxylate bridges is in all cases less than 0.1 cm−1, suggesting that no significant interdimer exchange coupling occurs in 1–4. A dependence of the interdimer coupling on the mutual orientation of the Ni2O2 planes was not observed. High-spin molecules of this sort are presumably only accessible with shorter bridging ligands such as oxalate or squarate dianions.