Force field calculations of the one pore model indicate that the formation of the hexagonal pore leads to a low steric demand of the bulky methyl benzoate functional groups, while in the rhombic pore the methyl benzoate groups are forced much closer to each other. This is especially prominent in the case of the short PDA linker. In the case of the longer benzidine, interaction of the methyl benzoate functional groups through the pore in the rhombic pore is still evident, but less pronounced than in the PDA case. This indicates that the steric interaction of the bulky functional groups, through the pore play a role in determining the formation of the net during the synthesis of the 4A2E-PDA-COF. It is difficult to predict, if the sql or kgm net are the "default" or more stable structure for a given linker, as weak interactions such as stacking play a role. However, based on the same aldehyde linker, only with different length diamines we observed a switch in the preference from the kgm for the smaller diamine to the sql for the longer diamine. This indicates that the longer benzidine linker allows the formation of the sql structure while the shorter PDA linker prohibits the formation of the sql and thereby favors the formation of kgm. COF based on a similar tetra aldehyde linker as reported here, but without the bulky functional groups was reported to favor the formation of the sql COFs for both the benzidine and PDA linkers. This supports the hypothesis, that the steric interactions drive the formation of the kgm lattice instead of the sql. We achieve a length dependent switch between the topologies for our COFs, which allows us to override those preferences via the weak interactions.