Phenalene
1H-Phenalene, often called simply phenalene is a polycyclic aromatic hydrocarbon. Like many PAHs, it is an atmospheric pollutant formed during the combustion of fossil fuels. It is the parent compound for the phosphorus-containing phosphaphenalenes.
The name was proposed by German chemists in 1922 as a contraction of periphenonaphthalene.
It has been discovered in interstellar space in the Taurus Molecular cloud as part of the QUIJOTE survey.