A simple and efficient synthesis of annulated 2,2'-bipyridinium salts with attached dihydrothiazole or dihydro-1,3-thiazine rings has been developed through tandem S-transalkylation/intramolecular ring closure of 2,2'-bipyridine alkyl sulfides. The structures were confirmed by X-ray crystallographic analysis. (c) 2005 Elsevier Ltd. All rights reserved.