The crystal and molecular structure of the mesogenic trans-4-n-butyl-(4’-cyanophenyl)-cyclohexane (PCH4) has been determined using single crystal X-ray diffraction data. The crystals belong to the monoclinic system with space group P2(1)/c, a=17.006(6), b=5.764(2), c=15.526(5)Angstrom, beta=96.73(1)degrees, Z=4. The structure of PCH4 has been solved by direct methods and refined to R-value of 0.0484 for 1779 observed reflections. All the molecules occur in their extended form. The crystal packing involves a centrosymmetric head-to-tail pairing of molecules, so that individual molecular dipoles are opposed. A cyano-cyano weak interaction is indicated.