Considering the 4-fold helicity of AR-11, we can depict ten stereoisomers including four pairs of enantiomers and two meso isomers (six diastereomers in total, Figure ), which are categorized as follows: C1 symmetry (C1-I and C1-II), C2 symmetry (C2-I and C2-II), and Cs symmetry (Cs-I and Cs-II) (Figure ). DFT calculations were performed to explore the relative stability of them. Calculation details are given in the Supporting Information (Figure S14-15). 11 Based on the DFT calculations, the (P,M,P,M) conformation is the most stable, which is consistent with the X-ray crystal structure result, followed by the alternated (P,M,M,P) (+0.9 kcal/mol). The conversion barrier of AR-11 from the (P,M,M,P) to the (P,M,P,M) is 20.1 kcal/mol (Figure ). Furthermore, AR-17 exhibits 6-fold helicity and affords 36 types of isomers with varying Gibbs free energies (Figure ). Semiempirical calculations were conducted over them. Based on the calculations, (P,M,P,M,P,M,P) conformation is the most stable, followed by the alternated conformation (P,M,P,M,P,P,M) (+0.8 kcal/mol).