This paper investigates the relationship between office buildings and their tenants. More specifically, we ask the question, whether the tenants of certified green office buildings differ in terms of credit-worthiness from the tenants of non-certified buildings. For the empirical analysis, we use data for Vienna, Austria. With this study, we want to relate two areas, which according to our knowledge are completely separated both in the theoretical discussion and in the current practice of the real estate and finance industry. This is quite surprising taking into account the central role of finance in real estate economics. Nevertheless, establishing a link between characteristics of buildings (certification as Green building) and of building tenants (credit rating) is potentially very important. Tenants with better credit ratings offer a lower risk of rent default and therefore higher property value when viewed from an income approach perspective. For the empirical analysis, we use data on buildings from public sources and ÖGNI (Austrian Green Building Council). Data on credit ratings come from Creditreform AG.