(2Z,2'Z)-Diethyl 3,3'-[butane-1,4-diylbis(aza-nedi-yl)]bis-(but-2-enoate).

The whole mol-ecule of the title β-enamino-ester, C(16)H(28)N(2)O(4), is generated by a crystallographic inversion center, situated at the mid-point of the central C-C bond of the 1,4-diamino-butane segment. There are two intra-molecular N-H⋯O hydrogen bonds that generate S(6) ring motifs. This leads to the Z conformation about the C=C bonds [1.3756 (17) Å]. The mol-ecule is S-shaped with the planar central 1,4-diamino-butane segment [maximum deviation for non H-atoms = 0.0058 (13) Å] being inclined to the ethyl butyl-enonate fragment [C-C-O-C-C=C-C; maximum deviation = 0.0710 (12) Å] by 15.56 (10)°. In the crystal, mol-ecules are linked via C-H⋯O inter-actions, leading to the formation of an undulating two-dimensional network lying parallel to the bc plane.