Novel 5-(2-chlorophenylmethylidene)-2-thio-4-imidazolinones 3 and 2-Alkythio-5-(2-chlorophenylmethylidene)-4H-imidazolin-4-ones 4 have been synthesized via a tandem aza-Wittig reaction to develop more imidazolinones that may possess biological activities. The target compounds were identified by GC-MS, IR, and 1H NMR spectroscopies, and element analysis, and, in the case of 4k, its structure was established by single crystal X-ray diffraction. They showed not only fungicidal activities against Gibberella zeae, Cercospora beticola, Fusarium oxysporium, Rhizoctonia solani, and Botryosphaeria bere...