Non-natural, sequence-encoded polyphosphates were prepared using the phosphoramidite approach on a DNA synthesizer. Two phosphoramidite monomers, namely, 2-cyanoethyl (3-dimethoxytrityloxy-propyl) diisopropylphosphoramidite (0) and 2-cyanoethyl (3-dimethoxytrityloxy-2,2-dimethyl-propyl) diisopropylphosphoramidite (1), were used in this approach to form binary-coded sequences. Using 1000 Å controlled pore glass as a support and a large excess of monomers at each step, it was possible to synthesize homopolymers and sequence-coded copolymers of high chain-length. For instance, monodisperse polymers containing 16, 24, 56, and 104 coded monomer units were synthesized and characterized in this work. These results indicate that highly efficient phosphoramidite steps are suitable for the synthesis of long non-natural information-containing macromolecules.