ABSTRACT4-Arylmethylene-2,4-dihydro-2-arylthioanilido-5-methyl-3H-pyrazol-3-ones(2) were prepared by the condensation of 2,4-dihydro-2-arylthioanilido-5-methyl-3H-pyrazol -3-ones (1) with aromatic aldehydes in the presence of glacial acetic acid. The synthesized compounds (2) reacted with phenyl thiourea in presence of alcoholic KOH at reflux temperature to give 1-arylthioanilido-3-methyl-4-aryl-6-phenylimino -4,7-dihydro-1, 3-thiazino [5,4-d] pyrazoles (3). The synthesised compounds (3) have been screened for their fungicidal activities against fungi A. fumigatus and C. albicans at different concentrations.