Crystal structures and Hirshfeld surface analyses of (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-phenyl­diazene, (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-methyl­phen­yl)diazene, (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-meth­oxy­phen­yl)diazene and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(3-methyl­phen­yl)diazene

The crystal structures and Hirshfeld surface analyses of four similar azo compounds are reported. (E)-1-[1-(4-tert-Butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-phenyl­diazene, C(18)H(18)Cl(2)N(2), (I), and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-methyl­phen­yl)diazene, C(19)H(20)Cl(2)N(2), (II), crystallize in the monoclinic space group C2/c with Z = 8, and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-meth­oxy­phen­yl)diazene, C(19)H(20)Cl(2)N(2)O, (III), in the monoclinic space group P2(1)/c with Z = 4. (E)-1-[1-(4-tert-Butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(3-methyl­phen­yl)diazene, C(19)H(20)Cl(2)N(2), (IV), crystallizes in the triclinic space group P [Image: see text] with Z = 4 and comprises two mol­ecules (A and B) in the asymmetric unit. In the crystal structures of (I) and (II), mol­ecules are linked by C—H⋯π and C—Cl⋯π inter­actions, forming layers parallel to ( [Image: see text] 02), while mol­ecules of (III) are linked by C—H⋯O contacts, C—H⋯π and C—Cl⋯π inter­actions forming layers parallel to ( [Image: see text] 02). The stability of the mol­ecular packing is ensured by van der Waals forces between these layers. In the crystal structure of (IV), mol­ecules are linked by C—H⋯π and C—Cl⋯π inter­actions, forming a tri-periodic network.