Single crystals of 3a were grown by slow diffusion of methanol into its solution in carbon disulfide/toluene with a volume ratio of 1:1. X-ray crystallographic analysis revealed a triply twisted Möbius geometry containing six saturated CH2-CH2 bonds (Fig. ). The existence of saturated single bonds in 3a effectively releases the strain during the cyclization reaction. Both (P,P,P)-and (M,M,M)-enantiomers have been observed in the crystal structure in equal amount, and they are arranged in an alternating mode in each layer, forming a tight two-dimensional polymer network with close π-π contacts (distances of 2.8-2.9 Å) (Fig. and Fig. in Supplementary Information). Between the adjacent layers, there exist multiple [CH…π] and van der Waals interactions (distances of 2.7-2.9 Å) (Fig. ), which result in a densely packed threedimensional (3D) structure (Fig. ). As for 1, although it has three long alkoxy substituents (-OC8H17), the fully conjugated and highly symmetric structure allows itself for high crystallinity. The single crystals of 1 were obtained from slow diffusion of methanol into its solution in 1,1,2,2tetrachloroethane. X-ray crystallographic analysis disclosed a fully conjugated, all sp 2hybridized, triply twisted Möbius topological structure (Fig. ). However, the (P,P,P)-and (M,M,M)-enantiomers of 1 are not equally found in the crystal structure but with a ratio of 1:2 (Fig. and Fig. in Supplementary Information). Some close π-π contacts (distances of 2.7-3.4 Å) are observed between two enantiomers for each layer and multiple [CH…π] and van der Waals interactions (distances of 2.7-2.9 Å) also exist between the adjacent layers (Fig. ). The sum of these short contact interactions and the existence of long alkoxy chains renders a relatively loose 3D structure of 1 in the single crystal as compared to 3a (Fig. ). Bond length analysis of 3a and 1 indicated a dominant double bond nature for the newly fused -CH=CHmoieties like kekulene and other cycloarenes (Fig. in Supplementary Information), indicating a localized aromatic character in these nanobelts (see further discussion below). ) for 1. The backbone structures with grey and yellow color represent (P,P,P)-enantiomers and (M,M,M)-enantiomers, respectively. The red and white color atoms represent O and H, respectively. The ORTEP drawing has 50% thermal probabilities. Some of the substituents were removed for clarity.