DNA is a highly flexible molecule with the ability to accommodate molecules with various shapes and sizes. From a purely spatial point of view, COSAN could form complexes with DNA either through intercalation or groove binding, albeit requiring major structural changes in DNA. However, COSAN is unable to offset such structural changes by forming new bonds. Additionally, regardless of DNAbinding mode, ligand interactions with DNA usually include an electrostatic component between the cationic ligand and anionic DNA, which anionic COSAN cannot provide. COSAN has no effect on DNA structure, length, stability, or hybridization, and DNA, in turn, does not affect the absorption spectrum or diffusion coefficient of COSAN or induce CD or LD signals. COSAN titration into DNA has no heat effects. Based on theoretical considerations and on our experimental results, COSAN cannot form complexes with DNA, and DNA is not necessary for COSAN to induce toxicity, which is most likely protein-or cell membrane-dependent. In conclusion, COSAN is DNA-neutral pharmacophore without significant interactions with DNA, thus confirming the general safety and biocompatibility of metallacarboranes.