Department of Chemistry, hoepartment of Zoology, J. N. V. University, Jodhpur-342 005, Rajasthan, India Manuscript received 5 September 2007, revised 16 January 2009, accepted 1 September 2009 Synthesis of some novel formazans have been carried out by the reaction of 2-mercapto-2-(methylamldo-2'-chloro-N-benzylidene)-3·phenyl-4-oxo·(3H)·quinazoline with diazotised solution of aromatic amines in pyridine and screened for their insecticidal activity against Tribolium confusum.