Nuc-DAOTA + (20 μM) itself does not show any features in the CD spectrum, but upon complexation with dsDNA (30 μg/mL) in PBS (10 mM, pH 7.4), showed extremely weak positive and negative ICD signals at 570 nm and 455 nm, respectively (Figure ). These poor ICD signals appeared in the absorbance spectral regions of Nuc-DAOTA + , indicated negligible minor groove interactions, since groove binders generally exhibit more intense ICD signals, while intercalators possess weak ICD signals. The central positive charge of the triangulenium aromatic core is also believed to participate in electrostatic interactions with the negatively charged phosphate backbone of DNA. Thus, we assumed that Nuc-DAOTA + , bearing an additional positive charge at the ammonium PEG-motif, binds with dsDNA molecules by incorporating multiple binding modes, including strong electrostatic interactions, intercalations, and π-π stacking interactions. The Nuc-DAOTA + also showed a similar CD response after binding with ssDNA, which could be from the participation of multiple modes of binding interactions of diazaoxatriangulenium dyes with nucleic acids (Figure , ESI).