Electrical properties of two-phase mixtures of copper(I) bromidewith titanium dioxide are investigated by impedance spectroscopy coupledwith X-ray diffraction and scanning electron microscopy. An increase ofconductivity of more than an order of magnitude with respect to purecopper(I) bromide is detected in the extrinsic domain. The results can beinterpreted in the framework of the brick-layer space charge model. Theimportance of OH groups on the surface of titania particles as preferredsites for internal adsorption of copper ions is confirmed. A maximum effecton conductivity is revealed for about 15 mol% of second phase andrelated to the microstructure of the composites.