The title compound, C(17)H(16)N(4)OS, is stabilized in the form of a two-dimensional polymeric network due to inter-molecular N-H⋯S and N-H⋯O hydrogen bonds. An intra-molecular N-H⋯N hydrogen bond forms an S(5) ring, whereas inter-actions of the N-H⋯O and C-H⋯S types complete S(6) ring motifs. π-π inter-actions with a centroid-centroid distance of 3.6514 (10) Å are found between the ethyl-substituted benzene ring and the heterocyclic ring of the isatin derivative.