A series of monomeric strands consisting of m-terphenyl backbones with chiral rigid C-linked (3) and flexible N-linked (5) formamidines and achiral carboxylic acid (4) and flexible carboxymethyl (6) residues were synthesized, and their duplex formations through amidinium−carboxylate salt bridges were investigated by NMR, circular dichroism (CD), and UV−visible spectroscopies. The salt bridge-derived