This article describes the synthesis and characterization of semicrystalline copolymer based on dihydroxy-terminated polystyrene and a uniform crystallizable diamide (T phi T or T6T) hard segment. The concentration of the diamide in the copolymer varies from 3 to 15 wt% by changing the length of soft segments using dimethylterephthalate as a chain extender. The inherent viscosity of the polymer is very high ranging between 1.6 and 2.9 dL/g. Differential scanning calorimetry spectrum shows T-g for soft and T-m for hard segment as expected for crystalline copolymer. The products are semicrystalline materials with a crystallization window of 3-9 degrees C. Depending on the amide concentration in the copolymer, the hard segments melting temperature ranged between 149 and 275 degrees C. Fourier-transform infrared spectroscopy (FT-IR) results show that the degree of crystallinity of the hard segment in the copolymer is very high, that is up to 97%. Temperature-dependent FT-IR shows that crystallinity is highly reversible with respect to temperature. Wide angle X-ray scattering data also confirm that the materials are semicrystalline in nature. The solvent resistivity of these materials is extremely high even at a low concentration of (3%) amide content. The entire polymer shows low water absorption, depending on the concentration of amide segments.