The most significant decrease in the number of polymorphs occurs when increasing the number of aromatic rings from 4 to 6. We attribute this trend to the changing shape of the molecule from [4] to [6]helicene, wherein the molecule adopts a quasi-flat shape for n = 4, but becomes increasingly helical on increasing n, thereby disrupting some of the stable interactions and thus polymorphs available to (quasi-)flat aromatic compounds. The change in shape of the helicenes with changing number of aromatic rings can be quantified by the change in angle between the terminal aromatic rings, as shown in (Fig. ). A similar, but less pronounced decrease in the number of low energy polymorphs is observed when n increases from 10 to 12, again likely due to the disruption of stable interactions when increasing the angle between the terminal rings. When the angle between the terminal rings is small, such as when n = 9, the molecule fills a more uniform space, leading to a larger number of similar packing motifs being energetically accessible. Conversely, the packing for helicenes with larger angles between terminal rings, such as [6] and [12]helicene, results in relatively fewer polymorphs. Interestingly, the proportion of enantiopure structures in the landscapes is highest for n = 6 and n = 12, implying that large angles between terminal rings, and thus non-uniform shapes, stabilises enantiopure structures relative to helicenes with more uniform shapes (Fig. ). This suggests that the stabilizing interactions that are lost when the molecular shape becomes less uniform occur predominantly in racemic structures rather than enantiopure.