Abstract 9, 10-Phenanthrenequinone forms α-oxo-oxetane (VIII) when irradiated with 3- acetyl-2 (3H)-oxazolone, and it gives adducts X-XII with 3, 4, 5-trisubstituted 2 (3H)- oxazolones IV-VI. Duroquinone forms spirooxetanes XIII and XIV on photocycloaddition with IV and V.