Diaminodiphenoxyalkanes (I) have been reported to be active schistosomicides^[3], but have a toxic effect on eyes^[4].Attempts have been made in tho present work to modify their structures so as to retain the therapeutic activity, but to eliminate the side actions, and the preparation of some bis (p-aminophenoxy) thiaalkanes (Ⅱ) and bis (p-aminophenoxy) dithiaalkanes (Ⅲ) is now reportod.