A complete synthesis of 2[1'(3', 5'-disubstituted pyrazolyl) methyl] 5- phenyl-1,3,4-thiadiazole V(a-b) and 1,2,4-trizole VI (a-b) is reported. Cyclocondensation of $beta$-diketones with etylhydrazino acetate hydrochloride yielded ethyl 3,5-disubstituted pyrazolyl acetate II(a-c) which on treatment with hydrazine hydrate resulted in the formation of their hydrazide derivatives III(a-c). These hydrazides, when treated with phenyl isothiocyanate, gave thiosemicarbazide derivatives IV(a-c), which were cyclised in the presence of con. $H_2SO_4$ and $NaOH$ to give V(a-b) and VI(a-b), respectively.