A 1,3-dipolar cycloaddition of 2-methylquinoline, tert-butyl nitrite (TBN) and alkynes or alkenes for the synthesis of biheteroaryls containing both isoxazoline/isoxazole and quinoline motifs has been developed. In this protocol, TBN serves as a convenient N-O source to convert 2-methylquinoline into intermediate nitrile oxides in situ.