The selena and thiadiazole rings have been fused on 1/2-thiachroman-4-ones
1 & 2, 4,9/4, 10-dithiahexahydrophenanthren-1-ones 9 & 10, D-homo-6, 11/7,
11-dithia-1,3,5(10), 8, 13(14)-gonapentaen-18a-ones 17 & 18 through their s
emicarbazones by reaction with selenium dioxide and thionyl chloride, respe
ctively. The new compounds are characterized by thier IR and H-1 NMR data.