The Mn III ions (Mn1, Mn2 and symmetry equivalent) are six coordinate and in JT distorted octahedral geometries, with the JT axes defined by the HO-Mn-NCMe vector in each case. The acetonitrile molecules are disordered over two positions within the calix [4]arene cavities, with Mn-N distances of ~2.34 and ~2.58 Å and N-Mn-O angles of ~169 and ~172°. The Mn II ions are also six coordinate, but with rather different geometries. The two central Mn ions (Mn5) have [Mn(OH)4(ORL)2] coordination spheres with Mn-O bond lengths in the range ~1.99-2.29 Å, and cis/trans angles of ~78-98°/163-172°. Mn3 and Mn4 have their coordination spheres completed by one MeOH and one dmf, affording [Mn(OH)2(ORL)2(Osolvent)2] with (highly) distorted octahedral geometries. For both, five of the six Mn-O bond lengths fall in the range ~2.1-2.2 Å (Mn3) and ~2.1-2.3 Å (Mn4). The sixth bond, to the L O-atom, is much longer (Mn3-O1 = 2.577(7) Å and Mn4-O4 = 2.424(7) Å). A search of the Cambridge Structural Database reveals that of over 93,000 Mn-O bond distance entries, only 325 are found to be between 2.5-2.6 Å, with 98.8% of the entries lying within the 1.8-2.5 Å range (Fig. Figure shows that the structure of 3 is also related to the compounds [Mn III 6Mn II 2Gd III 2(L)2(μ4-O)2(μ3- OH)2(μ-OMe)2(μ-OH)2(MeOH)4(dmf)8](NO3)2(H2O)2] (5) and [Mn III 4Mn II 4(L)2(μ3-OH)2(μ-OH)(μ- Cl)(H2O)(MeOH)(dmf)4] (6), which was the very first compound isolated with H8L. The metallic skeleton of 5 describes three vertex-sharing [Mn III 2Mn II Ln III ] butterflies, and that of 6 two vertexsharing [Mn III 2Mn butterflies. Indeed, from an inspection of the metallic skeletons of 3-6 (Fig. ) it is clear to see that it is the Mn III L metalloligand that directs structure formation, with the additional Mn II /Ln III ions encapsulated within this framework, connected via bridging hydroxides/alkoxides. What is also clear is that these encapsulated metal ions can be replaced, whilst maintaining the general structure. This is illustrated by complex 6 undergoing selective Mn II /Ln III substitution to form [Mn III 4Mn II 2Gd III 2(L)2(Cl)2(μ3-OH)4(MeOH)2(dmf)8], 7 (Fig. ). This mirrors the behaviour observed for TBC [4]. For example, the Mn II ions in 2 can be replaced in a stepwise fashion with Ln III ions, from [Mn III 2Mn to [Mn III 2Mn II Ln III ] and [Mn III 2Ln . The isolation of multiple, structurally-related compounds is reflective of the versatility of the bis-calix [4]arene ligand for the construction of polymetallic clusters where subtle changes in reactants/conditions can be exploited to direct the nature of the metallic core and associated physical properties.