X-ray diffraction study of some liquid crystalline 2,5-disubstituted 1,3,2-dioxaborinane derivatives reveals the existence of a partially bilayered smectic Ad phase in the terminally CF3 and OCF3 substituted derivatives, with the higher level of molecular overlapping in the formation of the dimer observed for the latter compound; and the dimeric density wave fluctuations in the nematic phase of CN substituted derivative.