Post Graduate Department of Chemistry, Bishop Moore College, Mavelikara-690 II 0, Kerala, India E-mail: reshdevu_pk@yahoo.co.in Post Graduate Department of Chemistry, NSS College, Pandalam, Kerala, India Manuscript received 11 January 2007, revised 5 July 2007, accepted 20 July 2007 The 2-amino-4-arylthiazole motif is an important structural clement in a variety of bioactive molecules. The (4+1) thiazole construction strategy adopted involves the synthesis of the [C-N-C-S) precursors, namely 1-aryi-3-(N-phenylbenzimidoyl) thiourea or 1- alkyl-3-(N-phcnylhcnzimidoyl) thiourea and the preparation of the C5 synthone, the halo acetylhetaroyl derivative. The optimized reaction conditions developed have thus lead to the preparation of live 2-(N-arylamino)-5-(indol-3-oyl)-4-phenylthiazofes and three 2 (N,N dialkylmnino)-5-(indol-3-oyl)-4-phcnylthiawles. The structure of these new compounds were assigned on the basis of elemental analysis, FTIR, 1H NMR and 13C NMR and screened for their antimicrobial activity.