Various interfaces with F₁₆CoPc as one of the partners are characterized by a charge transfer across the interface and a concomitant reduction of the Co central atom in these molecules. We summarize recent photoemission spectroscopy results and compare those to the data from equivalent interfaces comprising F₁₆CuPc. In the latter, the Cu center remains unchanged indicating the particular role of Co in F₁₆CoPc as the electron accepting site.