Provided is a composition which contains a mono- or bis-benzotriazole compound, an N-oxide thereof, or a mixture of at least two of the preceding compounds. Representative bis-benzotriazole compounds include 3,3′-bis-(2H-benzotriazol-2-yl)-5,5′-di-tert-octyl-1,1′-biphenyl-2,2′-diols. Representative mono-benzotriazole compounds include 3-(2H-benzotriazol-2-yl)-5,5′-di-tert-octyl-1,1′-biphenyl-2,2′-diols. These mono- and bis-benzotriazole compounds are useful as stabilizers of degradable polymers against the degradative action of ultraviolet light. Also provided is a method of making these benzotriazole compounds by oxidative dimerization of the corresponding monomeric benzotriazole or by reductive cyclization of the corresponding azo- compound.