The configurations of the four geometric mer-isomers in a new [Co(3, 3-tri)(amp)Cl]^2^+[3,3-tri=N-(3-aminoethyl)-1,3- propanediamine; amp=2- (aminomethyl)pyridine] system were assigned by using 2D NMR techniques such as gCOSY and NOESY. Solvent used was Me~2SO-d~6 with the central peak of the CD~3 septet as the reference (^1^3C, δ=39.37; ^1H; δ=2. 49 relative to SiMe~4). Comparing to the eluates from the chromatographic column, cation exchange media used was Dowex 50W×2 (H^+ form, 200～400 mesh; Biorad Compauy), the first band contains the m2, the second band contains the m4, the third band contains the m1 and the fouth band contains the m3.

Key words: COBALT COMPLEX, ISOMER, NMR SPECTROMETRY, STRUCTURAL ANALYSIS