From the CSP search of napthalene and [3]- [12]helicenes, the number of stable polymorphs obtained decreases with increasing helicene length (Fig. ). This phenomenon can be attributed to the fact that the longer the spiral shape of the molecule, the steeper the potential energy surface. This is likely due to the decreased directionality of interactions afforded by smaller molecular shapes. For example, large molecular cages have relatively fewer low energy polymorphs within their crystal energy landscape compared to smaller molecules such as benzene. Consequently, this reduces the configurational space of feasible solidstate formations. The number of polymorphs (red), percentage of which are enantiopure (blue), and angle between terminal rings (green), for napthalene and each helicene structure within 20 kJ mol -1 of the global minimum from each CSP search. As napthalene and [3]helicene are not chiral, the % of enantiopure crystals has been omitted.