The joint project "Microscopy and Optical Spectroscopy of Organic Layers (MOSOL)" between the ”Centre Interdisciplinaire de Nanoscience de Marseille” (CINaM) and the “Abteilung für Atom- and Oberflächenphysik” (AOP) at the Johannes Kepler University Linz (JKU) aims at the combined microscopic and optical investigation of organic molecular layers on metal surfaces. Both groups provide complementary expertise and methods: Low Temperature Scanning Tunneling Microscopy (LT-STM, STS) and non-contact Atomic Force Microscopy (nc-AFM) at the CINaM and Optical Spectroscopies (RDS, DRS) and Photoelectron Emission Microscopy (PEEM) at the AOP. Combining microscopic and spectroscopic techniques allows to correlate the structural and morphological properties of the molecular layers with their electronic and optical properties and to gain a deeper insight into the structure-property relationship of the organic layers. As a model system we will study the adsorption of dihydrotetraazapentacene (DHTAP) molecules on pristine and modified Cu(110) surfaces. The substrate modification is achieved by pre-adsorption of oxygen or nitrogen, inducing different surface reconstructions that significantly alter the structural, electronic and chemical properties of the Cu(110) surface. In this way, we want to explore the influence of the metal-organic interface on the adsorption and growth of the DHTAP molecules, their structure and orientation on the surface, as well as the ensuing electronic and optical properties of the organic layers.