A new method is presented to optimize the reactivities of a prepolymer for the solid-state polymerization of AA and BB type monomers to obtain high molecular weight polymers. The proposed method consists of blending the prepolymers of different end group mole ratios to maintain optimal reaction stoichiometry, and developing a computational procedure to calculate the molecular weight of the polymer in the solid-state polymerization. A molecular species model is used to calculate the molecular weight moments of the optimized prepolymer and to calculate the molecular weight development in a solid-state polymerization. The molecular weight moments of different polymer species in the prepolymer mixture are estimated by performing the dynamic simulations of a melt prepolymerization process model in conjunction with a numerical optimizer. The model simulation results show that the proposed method offers a significantly improved process performance to obtain high molecular weight condensation polymers in a solid-state polymerization. Bisphenol A polycarbonate is selected as an example to illustrate the proposed method. (C) 2008 Elsevier Ltd. All rights reserved.