Seven cyclic and noncyclic organic phosphates have been examined for the reactivity to polycondensation. Polyphosphate and polyphosphate ester having pendant tertiary amine salt groups are obtained from a cyclic organic phosphate having a primary amine salt group and a tertiary amine salt group by a molten organic phosphate phase/organic phase polycondensation method. A novel concept of the zwitterion polycondensation mechanism is proposed. The chemical structure of the resulting polymers was confirmed from infrared spectra, solid state P-31 and C-13 NMR spectra.