Abstract: Provided are nucleic acid compositions modified with intercalating aromatic compounds attached directly or indirectly through a linker arm thereto. Modifications to the nucleotides or to the oligo- or polynucleotides involve the pentosyl moieties, the abasic moieties (without a base) and the base moieties. Useful property changes are effected and can be measured or detected when such modified nucleic acids compositions have hybridized specifically to target nucleic acids.