The chromium(III) complexes with a new potential chromium transporting ligand-2,5-pyridinedicarboxylic acid (isocinchomeronic acid, icaH 2 ):[Cr(icaH) 3 ] 0 , [Cr(icaH) 2 (H 2 O) 2 ] + and [Cr(icaH)(H 2 O) 4 ] 2+ (where icaH = N,O-bonded isocinchomeronic acid anion), have been obtained and characterized in solution. The [Cr(icaH) 3 ] 0 complex undergoes aquation in acidic media to the diaquaproduct. Kinetics of this process was studied spectrophotometrically in the 0.1-1.0 M HClO 4 range, at I = 1.0 M. The first aquation stage, the chelate-ring opening at the Cr-N bond, is a much faster than the second one. The rate laws are of the form: k obs = k 1 + k -1 /Q 1 [H + ] and k obs = k 2 Q 2 [H + ]/ (1 + Q 2 [H + ]), where k 1 and k 2 are the rate constants for the chelate-ring opening and the ligand liberation, respectively, k -1 is the rate constant of the chelate-ring closure, Q 1 and Q 2 are the protonation constants of the pyridine nitrogen and 5-carboxylate group in the one-end bonded intermediate, respectively. The results are discussed in terms of potential pharmaceutical application of the complex.