This paper studies the photooxidation processes with the particpation of /sup 1/O/sub 2/ with aminophenalenones, which are very promising for use as dyes and luminophores. Phenalenone and its 2-, 3-, 4-, 5-, 6-, and 9-amino derivatives (II-VII) were synthesized by known methods. The individual state of the compounds was controlled by TLC on Silufol. The experiment showed that the introduction of an electron-donor substituent into the phenalenone molecule leads to increase in photostability, but degree of this increase depends on the position of the amino acid group in the ring. The photodegradation of 6-aminophenalenone in ethanol proceeds mainly with the participation of a singlet oxygen.