The copper(II) atom shows a typical Jahn–Teller distorted [4 + 2] octa­hedral coordination sphere.

A new polymorph of 2-(benzotriazol-2-yl)acetic acid, C8H7N3O2, crystallizes in the space group C2/c (Z = 8). The non-planar mol­ecule has a synplanar conformation of the carb­oxy group. The crystal structure features helices parallel to the b axis sustained by O—H⋯N hydrogen bonding which are similar to those in the known polymorph [Giordano & Zagari (1978 ▶). J. Chem. Soc. Perkin Trans. 2, pp. 312–315]. However, in the title structure, columns are formed by π–π stacking inter­actions between benzotriazole fragments of centrosymmetrically related adjacent mol­ecules [centroid-centroid distances = 3.593 (10) and 3.381 (10) Å] whereas π–π stacking inter­actions are not observed in the other polymorph. In the crystal of the title compound, C—H⋯O inter­actions are also observed.