All the remaining clusters 1-8 exhibit parallel orientation of the molecular planes (see 𝑅 𝑃𝐴1 values in Table ), with the extent of stacking varying from cluster 8, where only a small peripheral portion of the 𝜋 system is involved, to cluster 7, corresponding to a fully eclipsed arrangement. The twist angle preferentially adopts values close to 0° or around 50-60°, except cluster 3.2 (79°). This (almost) bimodal distribution may be related to the interplay between favorable 𝜋-orbital interactions, which are maximized with the perfect alignment of monomers, and 𝜎-orbital repulsion, which can be significantly relieved by increasing the intermolecular twist. The same reasoning has already been invoked to explain why conformation 3.1 is comparatively more stable than 7, a result also confirmed at the ADC(2) level.