Aryl alkyl ketones react readily with morpholine in the presence of sulfur in air and moisture stable ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate [bmim]BF4 to produce the corresponding thiomorpholides in high yields. The use of recyclable ionic liquids makes this process quite simple, more convenient and environmentally friendly. (c) 2006 Elsevier B.V. All rights reserved.