Have you ever wondered what an architect and a chemist have in common? Both love great design. An architect designs a house, based on the principle that form follows function. While a chemist looks at a protein target and claims that structure follows function. All proteins have three dimensional structures that are related to their functions in our body. We can cure many diseases by modulating specific protein targets. But how to find such a modulator, for example small drug like molecules? In my research I try to understand these three dimensional structures of proteins and associated function, as well as their modulators. This understanding helps me to predict their interactions and mechanism of action. I use computer aided drug design techniques to develop new small molecules with improved biological activities, especially for membrane bound proteins such as GPCRs, G-Protein Coupled Receptors. So that structure based rational design can help in finding new effective medicines.