Heptacene is an organic compound and a polycyclic aromatic hydrocarbon and the seventh member of the acene or polyacene family of linear fused benzene rings.

[1] This compound has long been pursued by chemists[2][3][4] because of its potential interest in electronic applications and was first synthesized but not cleanly isolated in 2006.

[5][6] Heptacene was finally fully characterized in bulk by researchers in Germany and the United States in 2017.

When on the other hand the dione precursor is dissolved in a PMMA matrix first, heptacene can be studied by spectroscopy.

[8] When dissolved in sulfuric acid the heptacene dication is reported to be stable at room-temperature for more than a year in absence of oxygen.