Crystal structure of 7-[(2E)-2-benzyl­idene-3-oxobut­oxy]-4-methyl-2H-chromen-2-one

Two independent mol­ecules (A and B) comprise the asymmetric unit of the title compound, C(21)H(18)O(4). There are significant conformational differences between the mol­ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl­methyl­idene)but­oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol­ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol­ecules is E. The crystal packing features C—H⋯O, C—H⋯π(ar­yl) and π–π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter­actions, which generate a three-dimensional network.