DFT calculations were used for molecular geometry optimization and obtaining potential energy scans of the dihedral angles. All calculations were performed with the Gaussian 16 package by using wB97xD method at 6-31G (d, p) basis set. In all calculations, the long alkyl side chains on both donor and acceptor moieties were replaced with methyl groups for simplification. To obtain the potential energy scans of a dihedral angle, molecular geometries relevant to the dihedral angle of interest were firstly optimized at the wB97xD/6-31G (d, p) level of theory. Afterwards, single point energy of the optimized molecule was computed when the dihedral angle was varied from 0° to 180° at 10° intervals while fixing the remaining dihedral angles (rigid scan). The resulting single point energies were then plotted against the respective dihedral angle to obtain potential energy plots.