A mild and eco-friendly protocol for the synthesis of 1,2,3-benzotriazine-4-(3H)-ones is described using saccharin as a cheap and efficient catalyst and tert-butyl nitrite as a diazotization reagent for the first time. The current method has advantages such as cost effectiveness, energy efficiency, and simple experimental procedure, good yield of the desired product, and metal-free and environmentally benign conditions.