In this work a microscopic cell model of crystallization incorporating solute rejection is coupled with the macroscopic heat transfer using a finite element procedure to study the evolution of crystallinity.,The role of coupling is analyzed using two contrasting polymers, polyethylene and polystyrene. Simulations of the solidification were carried out using both the coupled and the uncoupled formulations to elucidate the effect of coupling. Both polymeric systems considered were affected by this coupling on the evolution of the crystallinity; however, the initial solute content has more effect on the slower crystallizing system. An incremental stress model is also applied to predict the residual stresses generated during the crystallization of the two polymeric systems. It was found that the predicted residual stresses are significantly affected by coupling. Good agreement with experimental results was observed for crystallization half-time results from the coupled solution by incorporating solute segregation effects for high undercooling, but the deviation was more significant at lower undercooling. For the slow-crystallizing polymer, fair agreement was observed irrespective of the degree of undercooling. The results show that the solute segregation has only a secondary influence on these systems, especially compared to the effect of undercooling.