Copper(II) borate is an inorganic compound with the formula Cu<sub>3</sub>(BO<sub>3</sub>)<sub>2</sub>. It consists of copper atoms in their cupric oxidation state and orthoborate groups. In the 19th century it was proposed to be used as a green pigment to replace the very toxic paris green. It has been studied for its photocatalytic properties.
Copper(II) borate can be prepared by heating a stoichiometric mixture of copper(II) oxide and diboron trioxide to 900 ðC.