The present work is concerned with the interactions between a copper atom and an organic environment. We report photoemission spectra of the valence region and of the core levels for thin films of copper porphyrazine molecules with stepwise increased ligand size. The extension of the molecular ligand is obtained by linear benzoannelation. Specifically, the electronic structure and the metal-to-ligand and ligand-to-metal charge-transfer processes are investigated for the t-butyl substituted copper-tetraazaporphyrin, -phthalocyanine, -naphthalocyanine, and -anthracyanine using synchrotron as well as AlKalpha radiation. Information about charge-transfer processes is inferred as a function of the molecular pi-electron system from the ratios between the copper satellites and the main lines, for both the Cu2p and the valence regions of the photoemission spectra. The experiments were performed at the MBI-BESSY undulator beamline at the synchrotron radiation facility BESSY II.