A series of thio-substituted pyrimidine, benzoxazole, benzothiazole and triazole analogues were synthesized from Baylis-Hillman bromides in a clean and efficient way. The synthesized twenty new compounds were subjected to in vitro COX-1 and COX-2 inhibitory activity. Majority of compounds found to be highly selective COX-2 inhibitor. Seven compounds (16e, 16f, 16k, 16l, 16m, 16r and 16s) displayed anti-inflammatory activity at micromolar concentrations with IC50 values for COX-2 inhibition ranging from 2.93 to 5.34 μM compared to reference drug whose IC50 is 2.66 μM. All these seven compounds had very little COX-1 inhibition property and thus are suitable candidates for anti-inflammatory drugs with less gastrointestinal side effect.