Tetraphenylhexaazaanthracenes: 16π Weakly Antiaromatic Species with Singlet Ground States ConstantinidesChristos P. ZissimouGeorgia A. BerezinAndrey A. IoannouTheodosia A. ManoliMaria TsokkouDemetra TheodorouEleni HayesSophia C. KoutentisPanayiotis A. 2015 Tetraphenylhexaazaanthracene, <b>TPHA-1</b>, is a fluorescent zwitterionic biscyanine with a closed-shell singlet ground state. <b>TPHA-1</b> overcomes its weak 16π antiaromaticity by partitioning its π system into 6π positive and 10π negative cyanines. The synthesis of <b>TPHA-1</b> is low yielding and accompanied by two analogous TPHA isomers: the deep red, non-charge-separated, quinoidal <b>TPHA-2</b>, and the deep green <b>TPHA-3</b> that partitions into two equal but oppositely charged 8π cyanines. The three TPHA isomers are compared.