Based on the superior results observed for the LTR-III G4 in the UV/Visible titration studies, we chose to investigate the binding of (E)-and (Z)-1 to this DNA sequence in greater detail using a battery of structural techniques, namely 1 H NMR spectroscopy, circular dichroism spectroscopy and enhanced molecular dynamics simulations. Previous work by our group has identified that this combination of theoretical and experimental approaches is wellsuited to understanding the different binding modes of G4 DNA targeting molecules. Moreover, unlike the UV/Visible titrations which required isomerisation of the ligand before the experiments, these additional studies also allowed us to confirm the DNA-binding properties of our ligand could be controlled reversibly with photoisomerization taking place in situ.