The pyridyl rings adopt a dihedral angle of 34.2 o (interplanar angle) with respect to the adjacent 2,6-diisopropyl-phenyl ring. Further analysis of the structure shows that the PDI core of L 1 is slightly twisted, with an angle of 7.0 o between the naphthyl rings at either end of the perylene core and forms a dihedral angle of 87.5 o with the 2,6-diisopropyl-phenyl rings. Crystals of 1 were grown which gave good quality diffraction allowing determination of a 3D MOF structure. Co2(O2CR)4 paddlewheels (Fig. ) are linked via the 2,6-naphthalenedicarboxylate ligands into two dimensional sheets, which exhibit the anticipated sql-net, and are pillared by the bipyridyl L 1 ligands to create a pillared 3D MOF (Fig. ). Topological analysis 27-29 reveals a pcu net, a relatively common arrangement in pillared MOFs. The MOF adopts a doubly interpenetrated structure (Fig. ) leading to more efficient packing; despite this, inspection of the crystal structure reveals that the perylene core of the PDI ligand is considerably curved (Fig. ). Rectangular channels in 1, excluding interpenetration, have dimensions of 32.0 Å by 13.2 Å.