Both independent mol-ecules in the asymmetric unit of the tautomeric title compound, C(14)H(13)NO(3), a synthetic product obtained from 2-lithio-methyl-quinoline and diethyl oxalate, crystallize in the enaminone form with a Z configuration around the double bond. Intra-molecular N-H⋯O hydrogen bonds occur, generating an S(6) graph-set motif. In the crystal, weak inter-molecular C-H⋯O and π-π stacking inter-actions [centroid-centroid distances = 3.7020 (14)-3.7429 (13)Å] define a three-dimensional supra-molecular network.