Microwave synthesis technique opens new avenues for the synthesis of many compounds. A novel and simple method has been developed for the synthesis of 1-(2,4-dinitrophenyl) pyrazolidine-3,5-dione and 1-(2,4 dinitrophenyl)-3,5-dimethyl-1H-pyrazole derivatives under microwave irradiation. These compounds exhibit mild to moderate antimircrobial activity against different strains of bacteria (e.g. E. coli, P. aeruginosa, S. aureus and B subtilis) and fungi (e.g. C. albicans and A. niger). All these synthesised compounds have been characterised by employing various techniques like TLC, Elemental analysis, IR, NMR and MS spectra. In addition to this, the yields of these compounds have been compared with the same compounds, obtained by conventional heating procedures. And the results show that by microwave irradiation method, the product yield is either high or may be same but it takes a very short period of time for reaction. Moreover, this technique provides ecofriendly or green chemical pathway for the synthesis of these compounds. Thus, the microwave irradiation method is more useful than the conventional method because of the shorter reaction time, better yield, conservation of energy and ecofriendly nature.