Dielectric properties and molecular motion were studied by use of dielectric spectroscopy and differential scanning calorimetry for two blends, fully transesterificated polyarylate of bisphenol A with terephthalate/isophthalate (50/50) (PA)/polycarbonate of bisphenol A (PC) blends and PA/poly(ethylene terephthalate) (PET) blends. All the quenched PA/PC and PA/PET blends were amorphous and the glass transition temperature (Tg) was varied with the blends ratio according to Gordon-Taylor equation. The PA/PET blends with more than 60% of PET crystallized above the crystallization temperature. The PA/PC and PA/PET blends showed two dielectric relaxations, alpha above Tg and gamma below Tg, which are related to a glass transition and a local motion of short segment, respectively. The alpha relaxation moved to lower temperatures as PC or PET content increases, reflecting the lowering Tg faithfully. In the PA/PET blends, the static (epsilon(0)) and the limiting dielectric constant (epsilon(infinity)), and the increment (Delta epsilon) for the alpha relaxation decreases with increasing temperature and the decrease falled on one curve, independent of the blend ratio. Any ferro- and piezoelectricity were not observed for two blends.