Crystal structures and Hirshfeld surface analyses of methyl 4-{2,2-di-chloro-1-[()-phenyl-diazen-yl]eth-enyl}benzoate, methyl 4-{2,2-di-chloro-1-[()-(4-methyl-phen-yl)diazen-yl]ethen-yl}benzoate and methyl 4-{2,2-di-chloro-1-[()-(3,4-di-methyl-phen-yl)diazen-yl]ethen-yl}benzoate.

The crystal structures and Hirshfeld surface analyses of three similar azo compounds are reported. Methyl 4-{2,2-di-chloro-1-[()-phenyl-diazen-yl]ethen-yl}benzoate, CHClNO, (), and methyl 4-{2,2-di-chloro-1-[()-(4-methyl-phen-yl)diazen-yl]ethen-yl}benzoate, CHClNO, (), crystallize in the space group 2/ with = 4, and methyl 4-{2,2-di-chloro-1-[()-(3,4-di-methyl-phen-yl)diazen-yl]ethen-yl}benzoate, CHClNO, (), in the space group with = 2. In the crystal of (), mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains with (6) motifs parallel to the axis. Short inter-molecular Cl⋯O contacts of 2.8421 (16) Å and weak van der Waals inter-actions between these chains stabilize the crystal structure. In (), mol-ecules are linked by C-H⋯O hydrogen bonds and C-Cl⋯π inter-actions, forming layers parallel to (010). Weak van der Waals inter-actions between these layers consolidate the mol-ecular packing. In (), mol-ecules are linked by C-H⋯π and C-Cl⋯π inter-actions forming chains parallel to [011]. Furthermore, these chains are connected by C-Cl⋯π inter-actions parallel to the axis, forming (01) layers. The stability of the mol-ecular packing is ensured by van der Waals forces between these layers.