The prepn. of polycryst. TiO2 impregnated with a modified Cu(II)-phthalocyanine (TiO2-CuPc) is reported along with a study on the photocatalytic behavior of this system compared with bare TiO2 (both in the anatase and rutile form) and with TiO2 samples impregnated with non-functionalized com. phthalocyanine (TiO2-CuPc) or with metal free phthalocyanine (TiO2-Pc). The photocatalytic degrdn. of 4-nitrophenol was studied as a model. The presence of modified CuPc was beneficial only for TiO2 (anatase) while the com. non-functionalized CuPc was slightly beneficial for both TiO2 (anatase) and TiO2 (rutile). The metal free Pc did not show any beneficial influence on the photoactivity. A tentative explanation of the beneficial effect due to the presence of the Cu(II)-phthalocyanines both on the initial reaction rate and on the mineralization process is provided by taking into account intrinsic electronic and physico-chem. properties.