Alkylation of 2‐morpholino‐cycloalken‐1‐carbothionic acid anilides 1 and 2 with 1,3‐dibromopropane in a two‐phase system leads to 1‐morpholino‐cycloalken‐3‐aryl‐tetrahydro‐1,3‐thiazine‐2‐ylidene 3 and 4. Reactions of 2‐morpholino‐cyclopenten‐1‐carbothionic acid anilides 5 and 3‐morpholinothiocinnamic acid anilides 8 with 1,2‐dibromoethane yield 1‐morpholino‐cyclopenten‐3‐aryl‐thiazolidine‐2‐ylidene 7 and 2‐(2′‐phenyl‐2′‐oxo‐ethylidene‐3‐aryl)thiazolidine 9, respectively. Alkylation of 1‐indanone‐ and 1‐tetralone‐2‐carbothionic acid anilides 11 and 12 with dihalogenoalkanes yield 1‐oxo‐indanylidene‐ and 1‐oxo‐tetralidenethiazolidines 14, 16 and tetrahydro‐1,3‐thiazines 15, 17, respectively.