In this talk, I will present our work on DNA-controlled functionalization of single-chirality carbon nanotubes, using the photochemical Guanine oxidation reaction first reported by the Weisman group (ACS Nano, 2019, 13, 8222). By employing resonance Raman and fluorescence spectroscopy, we are able to reveal strong sequence-dependent modification of carbon nanotubes. We have also used cryo-EM to characterize the reaction product. Our results provide new insight into the reaction mechanism.