A new compound [CoⅢ(aea)(2,2′-bipy)]Cl·H2O (aea=N-(2-aminoethyl)asp artate, 2,2′-bipy=2,2′-bipyridine) was hydrothermally synthesized and structur ally characterized, which contains a new quadridentate ligand (aea) came from ma lic acid and ethylenediamine via in-situ reaction. The asymmetric molecules are interconnected through N-H...O hydrogen bond to form helical chains that are fur ther hold together into a two-dimensional network via the N-H...Cl hydrogen bond . The formation of aea can be considered as the substitution of hydroxyl group i n malate by ethylenediamino group, which presents a type of new in-situ ligand r eaction. CCDC: 222018.