In an earlier paper we considered the effect of polypropylene modified with maleic anhydride (MAGPP) on the properties of in situ composites based on polypropylene (PP) and a thermotropic copolyesteramide (Vectra B). In this paper we consider the effect of MAGPP on the properties of in situ composites based on PP and two different thermotropic copolyesters. It was observed that the MAGPP was nearly as effective in improving the properties for the copolyester systems as it was for the copolyesteramide system. The addition of MAGPP leads to finer and better dispersed fibrils of liquid crystalline polymer relative to the blends with no MAGPP added. These results were somewhat unexpected based on earlier reports which suggested that compatibility would be detrimental to the formation of fibrils.