Drug development strategy: Re and ^99mTc tricarbonyl complexes with a pyridostatin moiety as a G4-binding motif have been obtained through a post-conjugation strategy using Pz-COOH-M. Metalation was found to enhance the complexes’ cytotoxicity in two cancer cell lines; the ^99mTc congener was used to study binding and internalization. Possible uses of the complexes for DNA-interaction, cell and biodistribution studies are illustrated. More information can be found in the Research Article by E. Palma, A. Paulo and co-workers (DOI: 10.1002/chem.202400285).