The crystal structure and the molecular arrangement of 4′-pentyl-4-cyanobiphenyl (5CB) at 253 K are described. At 253 K the compound crystallized from pure ethanol as plates, as well as fine needles, both colourless. The crystal data for both crystal habits are within experimental error identical. The data for the plates were measured as:a= 8.249(5) Å,b= 16.022(4) Å,c= 10.935(3) Å β = 95.09(3)°, space group P21/a. Considering 2014 independent reflections, the structure was refined to a finalRvalue of 0.0588. In the case of the needles, with 1892 independent reflections,Rconverged to 0.0503. The torsion angle between the normals of the benzene rings in the biphenyl moiety was −26.3(3)°. Within the aliphatic chain an all-transconformation was given, but the orientation of the pentyl group relative to the plane of the attached aromatic ring was nearly vertical (− 90.5(3)°). The structure obtained is discussed in comparison with the lower homologues 1CB up to 4CB.