A general strategy for synthesizing pyrano/benzopyrano[2,3-c]pyrazol-6-ones has been developed through a C-H activation/cyclization tandem reaction from readily available N-hydroxyamides and diazopyrazolones. Broad substrate scope and excellent functional group tolerance highlight the versatility of this approach. The scalability of the reaction and the ability to perform diverse functional group transformations on the resulting benzopyrano[2,3-c]pyrazol-6-one derivatives further demonstrate its practical utility. Overall, this method overcomes the limitations of conventional synthetic routes, offering a general and efficient pathway for constructing this important class of compounds.