Fiber-reinforced terephthalate-co-4,4′-bibenzoate copolyester behaves like a liquid crystalline polymer, providing fast crystallization, short cycling times, high Tg and Tm, high strength and stiffness, while the viscosity is unexpectedly reduced at a low fiber loading ratio. In an injection molding process, the viscosity of the fiber reinforced copolyester at low fiber loading is reduced by increasing the fiber loading.