Crystal structures of methyl (E)-3-(2-chloro-phen-yl)-2-({2-[(E)-2-nitro-vin-yl]phen-oxy}meth-yl)acrylate and methyl (E)-2-({4-chloro-2-[(E)-2-nitro-vin-yl]phen-oxy}meth-yl)-3-(2-chloro-phen-yl)acrylate.

The title compounds, C19H16ClNO5, (I), and C19H15Cl2NO5, (II), both crystallize in the monoclinic space group P21/n. They differ essentially in the orientation of the methyl acetate group, with the C=O bond directed towards the NO2 group in (I) but away from it in (II). In compound (I), the mean plane of the methyl acrylate unit is planar, with a maximum deviation of 0.0044 (2) Å for the methyl C atom, while in (II) this deviation is 0.0147 Å. The inter-planar angles between the two aromatic rings are 74.87 (9) and 75.65 (2)° for compounds (I) and (II), respectively. In both compounds, the methyl acrylate and nitro-vinyl groups each adopt an E conformation about the C=C bond. In the crystal of (I), mol-ecules are linked by C-H⋯O hydrogen bonds forming chains along the b axis. The chains are linked via C-H⋯Cl hydrogen bonds, forming sheets parallel to the ab plane. The sheets are linked via C-H⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(30) ring motif. The dimers are linked via C-H⋯O hydrogen bonds, forming sheets parallel to the ac plane and enclosing R 4 (4)(28) ring motifs. The sheets are linked via parallel slipped π-π inter-actions (inter-centroid distances are both ca 3.86 Å), forming a three-dimensional structure.