In this paper, a brief review of the syntheses, characterization and anion-binding properties of core-modified octaphyrins is presented. It has been shown that the core-modified octaphyrins exhibit aromaticity both in solution and in solid state, confirming the validity of the (4n + 2) Huckel rule for larger π-electron systems. Solid-state binding characteristics of TFA anions of two core-modified octaphyrins are also described.

Expanded isophlorins are typical examples for stable anti-aromatic systems. Paratropic ring current effects are observed in their NMR spectra mainly due to their planar conformation. Herein we report the synthesis of the first twisted 40π expanded isophlorin and also its two-electron oxidation to a 38π dication. It sustains the twisted conformation for the 4nπ and (4n+2)π electrons. Due to the non-planar conformation, they do not display ring current effects in their respective 1H NMR spectrum. NICS calculations reveal the non-(anti)aromatic features for the neutral 40π and the 38π dication species.