In addition, while 16 (2-((2-ethylhexyl)oxy)-5-methoxyterephthalaldehyde) was highlighted as the best performing dialdehyde in relation to the synthetic screen, with 67% of its combinations resulting in the clean formation of a single topology (Figure ), it did not lead to any POCs. While the preferential reactivity of dialdehyde 16 follows literature observations where functionalising precursors with either alkyl or ether chains can increase their solubility, and therefore conversion to a single cage species, it can also result in low porosity due to the chains occupying the internal cavity (such as in B16, C16 and D16 in Tri 4 Di 6 topologies, Figure ). 9,54,55 However, when these side-chains are removed, such as in dialdehyde 4 which has the same terephthalaldehyde core as 16, in combination with the same triamines B and D, Tri 4 Di 6 cages may be formed with predicted internal cavity diameters exceeding 6 Å as a result of their structural rigidity and lack of chain occupancy.