The π–π* electronic absorption spectra of 1-amino-, 1,4-diamino-, and 1,4,5,8-tetraaminoanthraquinones were investigated by means of the polarized absorption spectra using stretched PVA sheets and theoretical calculations. Each of these compounds has four absorption bands in the near-ultraviolet region (210–340 nm) and one in the visible region. The bands of the aminoanthraquinones which appear in the visible region can be assigned to the intramolecular charge-transfer transitions associated with the charge migration from the ami no group to the carbonyl groups.

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Polarized absorption spectra of naphthalene and acenaphthene were measured in stretched PVA (polyvinyl alcohol) sheets below 46.5 kK, and the polarization directions of the electronic transitions of the compounds were determined experimentally: It has been confirmed that naphthalene has four electronic transitions in the near ultraviolet region at 31.3 kK, 34.7 kK, 44.6 kK and 45.5 kK, and these transitions are polarized along the x‐ (the long axis of the molecule), y‐ (the short axis), x‐ and y‐axis, respectively. In the case of acenaphthene, an additional y‐axis polarized electronic transition, corresponding to the forbidden transition (1 Ag ‐1Ag) of naphthalene, was found apparently at 41 kK.