Anodic fluorination of various nitrogen-containing heterocyclic propargyl sulfides using Et4NF . nHF (n=3,4) or Et3N . 3HF as a supporting electrolyte and fluoride ion source in dimethoxyethane provided the corresponding monofluorinated products in moderate yields. Fluorination took place selectively at the position a to the sulfur atom of the sulfides and the heterocyclic moieties were riot fluorinated at all. (C) 2001 Elsevier Science Ltd. All rights reserved.