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π-Conjugated macrocycles have been highly attractive due to their challenging synthesis, fascinating aesthetic structure and unique physical and chemical properties. Although some progress has been made in synthesis, the study of π-macrocycles with different structural characteristics and supramolecular interactions still faces major challenges. In this paper, two new single-bond linked macrocycles (MS-4T/MS-6T) were reported, and the corresponding vinyl-bridged heterocycloarenes (MF-4T/MF-6T) were synthesized by the periphery fusion strategy. Further studies have indicated that the structure of these four macrocycles is determined by both size and curvature, showing unique variations from nearly planar to bowl and then to saddle. Interestingly, the nearly planar MS-4T with a small size and the rigid saddle-shaped MF-6T show no obvious response to fullerenes C 60 or C 70 , while the bowl-shaped MS-6T and MF-4T demonstrate a strong binding affinity towards fullerenes C 60 and C 70 . What's more, two kinds of co-crystals with capsule-like configurations, MS-6T@C 60 and MS-6T@C 70 , have been successfully obtained, among which the former shows a loose columnar arrangement while the latter displays a unique three-dimensional honeycomb arrangement that is extremely rare in supramolecular complexes. This work systematically studies the π-conjugated macrocycles and provides a new idea for the development of novel host-guest systems and further multifunctional applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A cyclopenta-fused macrocyclic tetraradicaloid, MC4-S , containing alternating phenanthrene (Phen) and dibenzo[ b , d ]thiophene (DBTh) units was synthesized and isolated in single-crystal form. Compared with its all-carbon isoelectronic structure, CPTP-M , the incorporation of two sulfur atoms leads to a smaller radical character and a larger singlet-triplet energy gap. X-ray crystallographic analysis reveals that the spin-spin coupling through the DBTh unit is stronger than that through the Phen moiety. In addition, the electron-rich sulfur atoms also raise the energies of both the HOMO and LUMO in MC4-S , but the overall optical and electronic energy gaps are close to that of the CPTP-M . MC4-S displays global anti-aromaticity according to the NMR measurements and theoretical calculations (NICS, ACID and 2D ICSS), with a 36π ring current circuit along the all-carbon periphery excluding the two sulphur atoms. Its dication becomes globally aromatic due to the existence of a dominant 34π-conjugation pathway. This study sheds some light on the effect of heteroatoms on the electronic properties of open-shell polyradicaloids., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)