An achiral banana-shaped called F-490 liquid crystal has been examined by mean of polarizing microscopy, differential scanning calorimetry (DSC) as well as X-ray diffraction (XRD) and dielectric spectroscopy methods. The phase diagram of the compound is proposed. The F-490 forms crystal-like phases the B(4) and the B(3) on heating and the banana-like antiferroelectric phase B(2) as well the B(3) and the B(4) phases on, cooling. Moreover, the formation. of solid phase depends upon thermal history. Dielectric studies have been done with HP set-up in a wide frequency range of 0.01-1.5MHz using LINKAM 5 mu m cells. Dielectric dispersion as well as absorption were calculated front the data. On. the base these data the complex rotational dynamics of banana-shaped molecule have been. described. The layer thickness and the unit cell parameters of B-phases were determined on the base of XRD results.