We showed previously that amorphous pyrene-contain polymer networks can produce hydrogen photochemically from water in the presence of a sacrificial hole scavenger. Recently, Lotsch et al. reported that a more crystalline material, a 2-D pyrene-based COF, shows higher photochemical activity. While this material has in-plane conjugation, out-of-plane conjugation between the close-packed organic layers was also invoked as an important structural feature for high photocatalytic activity. Through-plane conjugation is a relatively common feature of pyrene-containing materials and pyrene itself has been described as "the fruit fly of photochemists" because it is known to have interesting packing-related photophysical properties for organic electronics. Here, we chose three pyrene-based molecules; tetraphenylpyrene (TPhP), 1,3,6,8-tetrapyridin-4-yl pyrene (TPyP), and 1,3,6,8-tetra(4'carboxyphenyl)pyrene (TBAP) (Figure ), which all form hydrolytically stable crystalline solids, to investigate the effect of molecular structure and extended crystal packing on photocatalytic hydrogen production rate.