Polycyclic aromatic hydrocarbons are a class of molecules of broad interest that has long
been explored by various spectroscopic techniques. The electronic spectroscopy of these
species is of particular interest since it provides a framework for the understanding of
the electronic structure of large polyatomic molecules. Such studies also allow the
systematic investigation of electronic relaxation mechanisms in large molecules. In this
review, we focus on the gas-phase experimental work on such systems and present the latest
progress. We also underline the challenges that remain to be tackled. A focus on the
understanding of the electronic relaxation pathways at work in gas-phase PAHs will also be
presented, as well as their possible manifestation in space.