The importance of chemically modified oligonucleotides grew over the last decades and resulted in increasing FDA and EMA approved drugs. The foundation of this trend is the underlying chemistry to modify oligonucleotides. In that context, the group focuses on efficiently modifying oligonucleotides during solid-phase oligonucleotide synthesis by either intercepting the synthesis cycle or by using artificial building blocks. Additionally, this approach enables practical and specific incorporation of chemical handles into an oligonucleotide.