A spectrophotometric study has been carried out on the colored products formed in the interaction of 1,2,3‐benzotriazole with ruthenium. Absorbance measurements by the mole ratio method gave definite evidence of two to one and four to one 1,2,3‐benzotriazole to ruthenium interaction products. The spectrophotometric data indicated that mole ratio products lower than two to one and/or higher than 4 to 1 are not formed in the reaction.