A method has been developed for the one pot synthesis of 1′-alkyl-1′,4′-dihydro-2.3′-biquinolyl-4′-thiones based on the reduction of 1-alkyl-3-(2-quinolyl)quinolinium halides with sodium borohydride and subsequent thiolation. 1′-Alkyl-1′,4′-dihydro- 2,3′-biquinolyl-4′-ones were obtained in close to quantitative yield by the oxidation of 1′-alkyl-1′,4′-dihydro-2,3′- biquinolyl-4′-thiones. ©2006 Springer Science+Business Media, Inc.