A novel class of bis selena and/or thiadiazoles were prepared by the reacti
on of semicarbazones of 3,6-dithiaoctahydrophenanthrene- 1,8-dione, 3,6-dit
hiaoctahydroanthracene- 1,8-dione and 3,7-dithiaoctahydroanthracene-1,5-dio
ne with SeO2 and SOCl2, respectively. The latter, in turn, were obtained fr
om 1,2-, 1,3- and 1,4-xylylenedimercaptoacetic acids.