Although porosity has been linked to increased photocatalytic hydrogen evolution activity for conjugated organics polymers and polymeric carbon nitride, many of the most active organic photocatalysts are in fact non-porous. This indicates that photocatalytic hydrogen evolution activity is not determined by a single factor: it is dependent on many variables. There is, however, compelling evidence that certain recurrent structural motifs are more desirable than others. In particular, studies involving COFs indicate that extended π-π stacking is linked to increased photocatalytic hydrogen evolution activity. ESF maps offer a method to search for such structural motifs systematically, particularly as predictions are now tractable for more complex molecules and can often be performed on a timescale that is much faster than the associated experiments (i.e., synthesis and crystallization of a new candidate molecule coupled with photocatalytic measurements).