The reaction between Co(OAc)2•4H2O and Hsal (salicylaldehyde) in a basic MeCN solution (see SI for full details) leads to the formation of pink single crystals after 3 days upon diffusion of Et2O into the mother liquor. Crystals of [Co16(sal)16(OAc)16]•16MeCN (1•16MeCN) were in a tetragonal cell and structure solution was performed in the P4/n space group. The asymmetric unit (ASU) contains one quarter of the formula, and symmetry expansion affords the wheel shown in Fig. . The metallic skeleton (Fig. ) describes a single-stranded, sinusoidal [Co wheel of approximate diameter, Co1•••Co1' = ~14.5 Å. The 'inside' of the wheel is stabilised by sixteen µ3-, syn, syn, anti-OAc ligands. Eight lie in the metal plane, with four above and four below the plane. The sixteen µ-sal ligands are arranged in a similar manner on the 'outside' of the wheel. Eight µ-sal ligands are in a belt around the periphery of the wheel, whilst four are above the plane, and four below (Fig. ). These out of plane µsal ligands form an interesting arrangement that is reminiscent of calixarenes, presenting a shallow hydrophobic pocket as a result. The magnetic unit between nearest neighbours contains one µ- A search of the Cambridge Structural Database (CSD) reveals approximately twenty [Co16] structures, with more than half being squares and tetrahedra stabilised by thia-and sulfonyl-calix [4]arenes. There are two other wheels, one comprising linked squares and cubes built with a bis-benzimidazolediol ligand, and one incorporating four linear {Co4} subunits constructed with polytriazolate ligands. Further symmetry expansion of the new pseudo-calixarene structure presented by 1 reveals a remarkable arrangement in which symmetry equivalent (s.e.) wheels pack to form tubular networks of capsules, and channels between the tubules. Inspection of the ring structure of 1 in space filling representation (Fig. , in the ab plane) shows a very small channel through the ring as a result of the syn, syn, anti-OAc ligands on the inside of the molecule. Symmetry expansion along the c axis gives rise to a dimer with the next s.e. wheel as shown in Fig. (in the ac plane). These pseudo-calixarene wheels lock together in the solid state through inter-digitation of the µ-sal ligands, with some OAc ligands also forming part of the space filling belt. This gives rise to an encapsulated space with a volume of ~272 Å 3 that is occupied by disordered solvent molecules (Fig. ). It was not possible to resolve this disorder given the high symmetry and diffuse nature of the electron density. Interdigitation continues along the c axis, forming infinite tubular stacks of capsules, and these pack as shown in Fig. to form solvent filled channels that run parallel through the extended structure. Single crystals of 1 are solvent dependent, but the nature of the extended structure will be studied further with a view to forming more stable analogues that can be desolvated and explored for potential guest transport to the interior of the cages.