Two novel classes of 2, 4-thiazolidinediones and 2, 4-oxazolidinediones with an ω- (azolylalkoxyphenyl) alkyl substituent at the 5-position were prepared and their antidiabetic effects were evaluated in two genetically obese and diabetic animal models, KKAy mice and Wistar fatty rats. A large number of the 2, 4-thia (oxa) zolidinediones showed potent glucose- and lipid-lowering activities. The antidiabetic activities of the 2, 4-oxazolidinediones were ...