Syntheses, crystal structures and Hirshfeld surface analyses of ( <i>E</i> )-1-[2,2-dichloro-1-(2,3-dimethoxyphenyl)ethen-1-yl]-2-phenyldiazene and ( <i>E</i> )-1-(4-chlorophenyl)-2-[2,2-dichloro-1-(2,3-dimethoxyphenyl)ethen-1-yl]diazene

The crystal structures and Hirshfeld surface analyses of two similar azo compounds are reported. (<i>E</i>)-1-[2,2-di-chloro-1-(2,3-di-meth-oxy-phen-yl)ethen-1-yl]-2-phenyl-diazene, C₁₆H₁₄Cl₂N₂O₂, (<b>I</b>), crystallizes in space group <i>P</i>2₁/<i>c</i> with <i>Z</i> = 4, and (<i>E</i>)-1-(4-chloro-phen-yl)-2-[2,2-di-chloro-1-(2,3-di-meth-oxy-phen-yl)ethen-1-yl]diazene, C₁₆H₁₃Cl₃N₂O₂, (<b>II</b>), in the space group <i>P</i>1 with <i>Z</i> = 4. In the crystal structure of (<b>I</b>), the mol-ecules form layers parallel to the (010) plane through C-H⋯π and C-Cl⋯π inter-actions and van der Waals inter-actions between these layers consolidate the packing. There are two symmetry-independent mol-ecules in the asymmetric unit of (<b>II</b>). In the crystal, mol-ecules are connected by C-H⋯O and C-H⋯Cl hydrogen bonds, forming a three-dimensional network. C-Cl⋯π inter-actions also contribute to the packing. The inter-molecular contacts in the crystals (<b>I</b>) and (<b>II</b>) were analysed using Hirshfeld surface analysis and two-dimensional fingerprint plots.