TOLYLTRIAZOLE (METHYLBENZOTRIAZOLE), is a mixture of 4 and 5 methylbenzotriazole. It is a well-known copper and high copper alloy corrosion inhibitor used in applications such as water treatment, engine coolants, metal working fluids, lubricants, and cleaners.

Sodium salt of Tolyltriazole is also available as 50% solution.