All three molecules have predicted structures with nearly perfect π-π overlap (overlap  1, Figure ), but these occur in high energy regions of their crystal structure landscapes, away from the global energy minimum and leading edge of the ESF maps. The structures in experimentally accessible regions are those with overlaps in the range 0.85-0.95, where TBAP structures show significantly higher overlap than TPhP and TPyP (blue peak in histogram; Figure ). This difference stems from the carboxylic acid groups in TBAP, which direct the molecule into crystal packings that favor π-stacks with strong π-π overlap. This demonstrates a global, predictable preference for TBAP to adopt favorable packing for charge transport compared to TPhP and TPyP, which may enhance charge-transport to the interface with water and the hole scavenger. While the global energy minima structures for both TPhP and TPyP also show π-stacking with a reasonable degree of overlap (0.863 and 0.857, respectively), an experimentally known structure of TPhP that sits well above the minima displays no πstacking, suggesting that these more 'optimal' structures may be kinetically difficult to access, at least for TPhP.