The synthesis of a series of methylene(methylimino) (MMI) linked oligodeoxyribonucleotide dimers modified at the 2'-position with fluoro and/or methoxy groups and their incorporation into different sequences has been accomplished. From these dimers, bis 2'-OMe MMI dimer was selected for further studies based on its synthetic accessibility and the increased thermodynamic stability conferred upon oligonucleotides incorporating this modification.