We envisioned that the treatment of 2‐acyl azobenzenes with tosyl hydrazine would produce the corresponding tosyl hydrazones along with the release of water, and then, the hydrozones would be easily transformed to 2‐aryl‐2H‐indazoles having 3‐alkyl‐ or 3‐aryl groups through intramolecular cyclization with concomitant release of molecular nitrogen and sulfinic acid under metal‐free conditions. Herein, we describe an efficient synthetic method for 2‐aryl‐2H‐indazoles having alkyl‐ or aryl groups at the 3‐position through intramolecular cyclization of tosyl hydrazone having an azobenzene moiety, which is generated in situ from the condensation of 2‐acyl azobenzene with tosyl hydrazine together with the release of water, molecular nitrogen, and sulfinic acid under metal‐free aerobic conditions. All of the examples produced the corresponding 2H-indazoles in quantitative yields. The present reaction was determined to have a wide substrate scope and good functional group tolerance.