Since the understanding of DNA organization and structure in vivo is so important, fluorescent staining techniques using organic DNA-binding molecules are required for biological research and medical diagnosis, including cellular imaging and DNA quantification.[1–5] However, membrane-permeable DNA-specific stains are uncommon. The minor groove binders 4', 6-diamidino-2-phenylindole (DAPI) and Hoechst 33258 are ...