The non-covalent interactions of the small organic molecules with DNA essentially depend on multiple binding modes, including minor groove binding, intercalations, agglomerations, or electrostatic interactions with the phosphodiester backbone of DNA. Using circular dichroism (CD) spectroscopy, we further investigated the structural properties of the complexes resulting from interactions between Nuc-DAOTA + and DNA. CD spectroscopy is a highly valuable technique for investigating the conformational changes in the helical structure of the nucleic acids and their complexes with organic molecules. Achiral small molecules with no CD signal, possess the ability to develop induced circular dichroism (ICD) features (>300 nm) after interacting with the polynucleotides and in this regard provide valuable information to understand the binding interactions. The CD spectrum of pure dsDNA (30 μg/mL) in PBS (10 mM, pH 7.4) illustrated the typical spectrum of standard B-form DNA duplex, with a positive signal at 275 nm and a negative signal at 247 nm raised from the stacking-base-pair interactions and helix twisting, respectively and a cross-over point (from positive to negative) appeared at 263 nm (Figure ).