Poly-adenosine diphosphate ribose (poly-ADPr) is an important biopolymer which is synthesized by poly-ADPr polymerases (PARPs) and occurs as a post-translational modification of various proteins and enzymes. ADPr-chains can be either linear or branched. Although the involvement of ADPr in many cellular processes has become clear over the past decades, the mechanism of its action and in particular the role of branched ADPr structures in the signaling events remains elusive. Synthetic well-defined structures are essential to get a better understanding of the function of branched ADPr at the molecular level. In this project, we aim to develop a synthetic methodology towards branched ADPr chains.