Reaction of N-confused porphyrin 2 (2-NCH 2C 6H 5NCTPPH) with silver(I) trifluoroacetate in CH 3CN gave a good yield of the related silver(III) complex [Ag 2(2-NCH 2C 6H 5NCTPP) 2] 2+·[Ag 2(O 2CCF 3) 4] 2− ( 3). The oxidation state of the central metal in complex 3 was inferred from the diamagnetic NMR spectrum. The square-planar structure of this Ag(III) complex was elucidated by X-ray single-crystal analyses. X-ray diffraction analysis shows that the anion of complex 3, ( 3 A ; [Ag 2(O 2CCF 3) 4] 2−), contains two different bonding modes of the fluorocarboxylate to the Ag atoms, including the first example of the terminal bidentate η 2 mode. The free energy of activation at the coalescence temperature T c and thermodynamic parameters for the isomerization process between the form I (windmill) isomer of 3 A , I( 3 A ), and the form II (paddlewheel) isomer of 3 A , II( 3 A ), in CD 2Cl 2 solvent of the disilver compound is found to be Δ G 221 ≠ = 9.29 kcal / mol and Δ H = −257 cal/mol, respectively, through 19F NMR temperature-dependent measurements.