“…The triangulene (4,8,12-trioxa-4,8,12,12c-tetrahydrodibenzo[ cd,mn ]pyrene) compounds share a structure consisting of six aromatic rings arranged in a triangular fashion. , The all-carbon triangulene is not a stable molecule but can exist as either biradical or dianion. , The synthesized triangulenes contain heteroatoms and can be divided into two groups depending on the nature of the central atom. Figure shows the charged triangulenium − compounds ( A ) where the central atom is carbon, and the heterotriangulenes ( B ) with nitrogen − or phosphor , in the central position. Triangulenium compounds have also been synthesized with saturated carbon and oxo groups in the bridge positions. ,,,− …”