The synthesis of C4-linked imidazole C-0- and C-2-2'-deoxyribonucleoside phosphoramidites (dPAs), in which the final phosphitylations are greatly improved by 4,5-dicyanoimidazole-promoted conversion, is described. The respective dPAs are successfully incorporated into the sequence of a 15-nt DNA, and the abilities of one or two imidazoles to pair with different bases are investigated through thermal melting (T-m) experiments on the resulting DNA duplexes. Furthermore, computational models of the imidazole-modified DNAs are found to be in good agreement with the results of the thermal melting experiments.