AbstractThe quinoline‐monoacylhydrazidate‐coordinated transition‐metal compound Cd(QLH)2(H2O)2 (1) (QLH = 2,3‐quinoline dicarboxylhydrazidate) was obtained by the hydrothermal in situ acylation reaction between 2,3‐quinoline dicarboxylic acid and hydrazine hydrate. X‐ray single‐crystal diffraction analysis reveals that compound 1 features a mononuclear structure. Through the O–H···O and C–H···O hydrogen bonds between the neighboring molecules, the mononuclear units of 1 aggregate together into a 3D supramolecular network, which is stabilized by offset face‐to‐face π···π interactions. Compound 1 was characterized by IR spectroscopy, elemental analysis, TGA, and photoluminescence analysis, and it shows good photoluminescent property in the solid state at room temperature. In order to understand the emission mechanism, DFT calculations were carried out on the excited electronic states of compound 1.