Summary The surprising formation of C22H32N2S2 from the title compound L at 45'C involves the interaction of the basic adaaentanethione S-mathylide (1) with its acidic pre- cursor 1, in the course of which the anion 5 undergoes electrccyclic ring opening: the aci;i and base functions offer the clue to a prolific chemistry of the thiadia- zoline 1 and the thiccarbonyl ylide 2. - ... When the 1,3,4_thiadiazoline 1 was heated in xylene at 80°C, 96% N2 were