We next consider one-dimensional energy landscapes along some of the torsion angles suggested in Fig. . For the ROY molecule, intramolecular conformations found in its crystal polymorphs differ primarily by a single dihedral angle that is indicated in Fig. . Dihedral angles between ≈ 50-130 • disrupt the π conjugation between the two aromatic rings, leading to a larger band gap and polymorphs that are yellow in color ("Y-"). More planar conformations increase the extent of π delocalization and shift the color towards red (polymorphs named "R-") or orange ("O-").