The development of new medicines is a very long and complex process. It starts with the initial target identification and validation, followed by assay development. High throughput screening can identify hit compounds, which require further validation and testing, followed by lead discovery. The next steps are lead optimization, toxicology and formulation experiments. Only if all of these steps are successful a candidate substance will enter the preclinical development stage. The Drug Discovery Hub Dortmund will conduct several proof-of-concept projects starting from four different stages of the drug development process.