The Ni(II)-complexes of α-amino acids: L-Asparagine (L-HAsn), L-Glutamine (L-HGln) and Aspartic acid (L-H2Asp) were synthesized by easy, efficient, clean and environmentally benign method. The synthesized complexes were characterized by elemental analysis, conductivity measurements, magnetic moment and spectral analysis. The elemental analysis data of the investigated complexes revealed their 1:2 (metal to ligand) stoichiometries and monomeric nature and very low molar conductance values show the non-electrolytic nature of the complexes. The infrared spectral studies revealed the monobasic bidentate (N & O donor) nature of the amino acid ligands which coordinated through amino-N and carboxylate-O with Ni2+ ion in the complexes. The magnetic moment values and electronic spectral studied indicated the octahedral geometry of the investigated complexes. These complexes contain 5-membered chelate rings formed via the coordination of amino-N and carboxylate-O donors. The overall stability constants, which are the products of the stepwise stability constants of the octahedral (K1×K2) metal-amino complexes, are very high, revealing good stability and the stability order of the complexes is as follows: