The reaction of the 2-amino-substituted 1,3,4-oxadiazoles 9, 10 and the benzothiazoles 11, 12 with ethyl cyanoacetate is described. The obtained cyanoacetamide derivatives 13-16 gave the benzylidene derivatives 18-21 by condensation with benzaldehyde. 2-Phenyl-5-amino-1,3,4-oxadiazolo[3,2-a]pyrimidin-7-one (17) was also obtained. Moreover, the preparation of 6,7,8,9-tetraydro-5H-1,3,4-thiadiazolo[2,3-b]quinazolin++ +-5-thio-derivatives 22-25 and N-(1,3,4-thiadiazol-2-yl-5-substituted)-3,4-5,6-tetrahydro-anthran ilic acids 26-29 is also described. All above compounds and compounds, related to them, 1-8 were tested for their analgesic and antiinflammatory activities and the pharmacological screening results are reported and discussed.