AbstractThe product 2 in the 1,3‐dipolar cycloaddition of one equivalent of diazomethane top‐toluquinone (1) was determined by 250 MHz nmr spectra to be approximately 85% 6‐methyl‐1‐H‐indazole‐4,7‐dione (2b). X‐ray crystallographic analysis was employed in the characterization of 1,6‐dimethyl‐1‐H‐indazole‐4,7‐dione (4a), which was the major 1‐N‐methyl regioisomer in the methylation of the cycloaddition mixture 2 with diazomethane. Methylation of the cycloaddition product 2 with diazomethane also provided a regioisomeric mixture of the 2‐N‐methyl derivatives 5. This mixture was synthesized for characterization by an independent method which utilized the cycloaddition of 3‐methylsydnone (10) to toluquinone (1). 1,5,6‐Trimethyl‐1‐H‐ind‐azole‐4,7‐dione (9) was found to be a minor product in the reac