To enhance the yields of cage-forming reactions, high, or pseudo-high, dilution conditions are often employed, as are relatively rigid precursors. Alternatively, templates can be used to pre-organise components and promote formation of the desired architecture (Fig. ). The predictable coordination geometry of transition metal ions can make them very useful for such applications. Raymond, for example, demonstrated the efficiency of using an iron(III) template (Fig. ) to pre-organise catecholate units that were subsequently linked via amide bond formation with triamine 64, forming the iron complex of the cage (67) in 70% yield; by comparison, the [3+2] condensation of bis-acid chloride 63 with 64 under high dilution yielded cage 65 in 3.5% yield. Step-wise formation of a porphyrin nanoball via a macrocyclic intermediate was achieved using sequential coordination templates by Anderson and co-workers. Postsynthetic modification of pre-formed coordination cages, followed by demetallation, has also been used. Guest templates that interact with the incipient cage framework via alternative interactions, such as π-π 110a,b and hydrogen bonding, 120 have also been reported. Alternatively, assemblies can be initially formed under thermodynamic control using dynamic bonds, with subsequent modification used to kinetically "lock" the structure. A number of examples have been reported of transforming POCs into COCs through transformation of imines to amines, 121 amides, 122 aminals, 123 carbamates, 124 quinolines, 125 hydrocarbons, 126 and, through an azedefluorination reaction of a reduced amine with an isocyanate, cyclic ureas. In a similar vein, Yamogo and coworkers reported the transformation of a Pt6L4 octahedral coordination cage (68) into a COC (69) through reductive elimination (Fig. ). 128 Fig. Templates can be used to increase the yields of covalent cages formed under kinetic control through pre-organisation of a thermodynamic precursor.