A new β-diketone on the base of acetilacetone – 3-[(4-metoxidiphenyl)diazenyl]pentane-2,4-dion has been synthesized. Its molecular and crystal structure was solved by using of X-ray difraction  methods. The crystals are monoclinic: a=8.019 (6), b=6.379(4), c=10.941(8) Å, β=94.430 (13)⁰, V=557.9(7) ų, space group P2₁/m, Z=2, density (calculated) 1.394 g/cm³_­­, absorption coefficient 0.102 mm^-1, crystal size 0.20×0.30×0.27 mm³. It`s been found out, that synthesized compound belongs to hydrazo-form.