Triheterocyclic thiazoles containing coumarin and carbostyril (1-aza coumarin) have been synthesized by the reaction of the in situ generated 4-thioureidomethyl carbostyril and 3-bromoacetyl coumarins. The new compounds have been tested for their in vivo analgesic and anti-inflammatory activities. Qualitative SAR studies indicate that, the chloro substitution at C-7 in carbostyril and 6,8-dibromo substitution in the coumarin ring enhance anti-inflammatory activity. These compounds were also found to provide significant protection against acetic acid writhing in animal models. All the compounds have been characterized by IR, (1)H NMR, (13)C NMR and mass spectrometry.