Detail dielectric measurements were carried out on two different liquid crystalline (LC) samples formed by bent core (BC) molecules, showing B1 and B2 phases in the temperature range 100-150 degrees C. The thermal variation of real part of dielectric permittivity (epsilon ') represents a tiny dip only in the saturated B1 phase which might arising from the dipole orientation disorder due to the inherent phase instability. The experimental data have been used to determine different relaxation parameters. Evidently only one relaxation mode has been detected in the dielectric relaxation spectrum for both phases, which is attributed to the long axis molecular rotation process.