4,4′-bis(pentyloxy)azoxy benzene, C22H30N2O3, forms a mesophase at 341.5 K and melts at 396.2 K, with an intermediate highly ordered smectic phase. The crystal structure is triclinic P[unk], Z = 2 with a = 7.428(2), b = 8.267(1), c = 17.868(3) Å, α = 97.73(1), β = 98.66(2), γ = 101.25(2)°, Dc = 1.323, Dm = 1.289 g/cm3. The structure was solved using MULTAN80 and refined by full-matrix least-squares calculations to R = 0.0427 for 1960 observed reflections [I > 2.50 σ (I)]. The molecules are in their most extended trans conformation. They are nearly planar and packed in alternate sheets in which all the molecular long axes are either in head or tail configuration.