The dielectric properties of the third (3. OAOB) and fifth (5. OAOB) members of the PAA homologous series have been investigated in the frequency range from 0.1 to 12 MHz. Negative dielectric anisotropies have been obtained in the nematic phase of both substances. For the dielectric relaxation processes observed parallel to the nematic director, the relaxation times and activation energies have been estimated and discussed.