Abstract- In studies of polycyclic aromatic hydrocarbon carcinogenicity three dibenzopyrenes have been named as the strongest mutagens together with the frequently studied benzo[a]pyrene. A detailed study of the electronic structure of one of the three compounds, dibenzo [a, i] pyrene, was performed several years ago. Here we present a similar study of the two remaining compounds, dibenzo [a, h] pyrene and dibenzo [a, e] pyrene. The studies include electronic linear dichroism spectra, fluorescence polarization spectra and quantum mechanical calculations for both molecules, as well as vibrational linear dichroism spectra for the former of the two.