A thiophile-promoted one-pot synthesis of trisubstituted 1,3,5-triazines starting from isothiocyanates, N,N-diethylamidines, and carbamidines has been studied. The reaction proceeds through the formation of intermediary amidinothioureas, which react with carbamidines in the presence of mercury(II) chloride to generate the desired 1,3,5-triazines in good to moderate yields (40-70%). (C) 2010 Elsevier Ltd. All rights reserved.