This paper presents the synthesis and comprehensive analysis of a highly contorted and doubly negatively curved multihelicene compound, composed of three carbo[7]helicene units fused within a central six-membered ring. The synthesis of this compound involved a [2 + 2 + 2] cycloaddition reaction of 13,14-picyne, employing a Ni(0) catalyst, which exhibited superior performance compared to conventional Pd(0) catalysts. The evaluation of aromaticity in this triple carbo[7]helicene, utilizing magnetic and electronic criteria, led to noteworthy insights challenging the limitations of Clar's model of aromaticity.

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Cationic polycyclic aromatic compounds containing one or more nitrogen atom(s), also known as azonia polycyclic aromatic compounds, form a valuable class of molecules because of their fluorescent and/or medicinal properties. N-Arylated hydroisoquinoline derivatives were synthesized through an aryne aza-Diels–Alder cycloaddition/N-arylation sequence. A subsequent two-electron oxidation allowed to synthesize some axially chiral cationic benzo[c]phenanthridinium derivatives. The structural and optical properties of some of these molecules were determined. Their chirality was evidenced experimentally by single-crystal X-ray diffraction and 1H NMR spectroscopy, and their conformational behavior was examined by computational DFT methods.