The crystal structure of 5-{[(4′-heptoxy-biphenylyl-4-yl)oxy]carbonyl}-1-pentyne({A3E′O7}) was investigated by wide angle X-ray diffraction(WAXD), transmission electron microscope(TEM) and atom force microscope(AFM). The structures of A3E′O7 solution-crystal and melt-crystal are the same. The crystals belong to the monoclinic P112/m space group, the cell parameters are {a0.589 nm}, b0^771 nm, c4.75 nm, αβ90° and γ93.8°, the calculated cell density is {1.167 g/cm+3}. The crystal structure of 5 - {[(4’-heptoxy-biphenylyl-4-yl) oxy] carbonyl} -1- pentyne ({A3E’O7} was investigated by wide angle X-ray diffraction The structures of A3E’O7 solution-crystal and melt-crystal are the same. The crystals belong to the monoclinic P112 / m space group, the cell parameters are {a 0.589 nm }, b0 ^ 771 nm, c4.75 nm, αβ90 ° and γ93.8 °, the calculated cell density is {1.167 g / cm + 3}.