1. The electronic absorption spectra of nitrogen-containing derivatives of anthraquinone and chrysophanol have an aromatic character. 2. Absorption bands at 2700 and 3200 A are characteristic for the nitrogen-containing derivatives of anthraquinone, whereas an absorption band with a maximum at 4300 A is characteristic for the derivatives of chrysophanol. 3. Introduction of polar substituents, such as OH or NH2, into the anthraquinone molecule leads to the formation of a strong intramolecular hydrogen bond with carbonyl groups. In the IR spectrum of chrysophanol the frequency of the vibrations of the carbonyl group is reduced as the result of the formation of such a band. 4. In the vibrational spectra of nitrogen-containing derivatives of chrysophanol, no reduction in the vibrational frequency is observed in contrast to the case with the corresponding derivatives of anthraquinone.