The miscibility in blends of random liquid crystalline copoly(oxybenzoate-ethylene terephthalate) at a molar ratio of 60:40 (P64) and semicrystalline poly(ethylene-2,6-naphthalene dicarboxylate) (PEN) were investigated with differential scanning calorimetry, wide angle X-ray diffraction and polarized optical micrography. It was found that P64 and PEN were partially miscible as evidenced from the appearance of a single glass transition temperature for each blend at different compositions. Furthermore, the Flory-Huggins interaction parameter, chi(12), for P64 and PEN was determined to be -1.13 through the melting point depression analysis, indicating miscibility in blends of P64; and PEN at the melt state. The coherence lengths of PEN in the presence of a small amount of P64, around 3%, were larger than that in pure PEN, implying the regularity of PEN crystals in the blends with low P64 content being more perfect than that of the pure PEN.