The 1 H NMR spectra (aromatic region) of 2a, 2b, and 1 in 1,1,2,2-tetrachloroethane-d2 are shown in Fig. and 2D ROESY technique was used for the detailed assignment (Fig. in Supplementary Information). The chemical shifts for 2a and 2b are almost the same, indicating that the protons of both molecules are in a similar chemical environment. The 1 H NMR spectrum of 1 has two additional doublet peaks in the aromatic region, which originate from the dehydrogenated saturated bonds (-CH2-CH2-). The peak for the central benzene ring in each THBT unit in 2a/2b (δ = 7.1 ppm) was shifted to a lower field in 1 (δ = 8.2 ppm), resulting from a fully π-conjugated skeleton with a dominant local aromatic character. The variabletemperature (VT) NMR spectra for these three compounds did not exhibit obvious change with temperature elevation (Fig. -S4 in Supplementary Information) due to their rigid and twisted skeletons. Nuclear-independent chemical shift (Fig. in Supplementary Information) and anisotropy of the induced current density (Fig. -S25 in Supplementary Information) calculations on 2a/2b and 1 suggest a dominant localized aromatic character, in accordance with the bond length analysis. 3D isochemical shielding surface (ICSS) calculations reveal that the shielding regions (depicted in blue) are mainly located on the backbone of 2a/2b and 1 (Fig. -b and Fig. ). The deshielding regions (depicted in red) for 2a/2b are along with the shielding region but interrupted at the saturated bonds. On the other hand, the deshielding region of 1 intertwines the shielding region and forms an interesting trefoil strip (Fig. ), which is similar to the boundary of a triply twisted trefoil knot. To further understand the electronic structure of 1, the localized orbital locator isosurface of π orbitals (LOL-π) calculation was also performed. The map of LOL-π reveals that 1 has just one phase of π orbitals which are delocalized along the whole skeleton (shown in red, Fig. ), confirming a fully conjugated structure with single π-surface.