Owing to two unsymmetrical －NH~2 groups sited on different terminals, L-lysine was used as a reactant for synthesizing a novel unsymmetrical Schiff base with salicylaldehyde on one side and 2,4- dihydroxy benzaldehyde on the other one. Eight new lanthanide complexes with the ligand above were synthesized and characterized by elemental analysis, TG-DTA, molar conductivity, IR and EPR spectra, especially by a 500 MHz NMR spectrometer for 2D ^1^3C-^1H COSY and their high resolution solid state ^1^3C NMR spectra. The synthesis method, formation mechanism, coordination sphere of the complexes have been suggested as well. The results obtained may provide a new promising method for synthesizing the similar unsymmetrical Schiff bases and their complexes.

Key words: SCHIFF BASE, LYSINE, SALICYLIC ALDEHYDE, ELEMENTAL ANALYSIS, INFRARED SPECTROPHOTOMETRY, PROTON MAGNETIC RESONANCE SPECTROMETRY, RARE EARTH METAL COMPLEX