Dissolution of [(CH3)N](2)Na[MnN(CN)(5)] center dot H2O in water results in the rapid dissociation of the trans-CN- ligand to form trans-[MnN(H2O)(CN)(4)](2-)(aq), which reacts with monodentate pyridine ligands such as 3-methyl and 4-methyl pyridine to form the corresponding mono-substituted complexes, of which the molecular structures obtained from X-ray crystallography, trans-[MnN(3-pic)(CN)(4)](2-) and trans-[MnN(4-pic)(CN)(4)](2-), are reported. [MnN(H2O)(CN)(4)](2-)(aq) also reacts with bidentate nudeophiles such as pyridine-2-carboxylate (pico) and quinoline-2-carboxylate (quino), yielding the corresponding [MnN(eta(2)-pico)(CN)(3)](2-) and [MnN(eta(2)-quino)(CN)(3)](2-) complexes as determined by X-ray crystallography. The formation kinetics of pyridine-2-carboxylate and three different pyridine-2,x-dicarboxylate ligands (x = 3, 4, 5) are reported, and two consecutive reaction steps are proposed, defined as the formation of the [MnN(eta(1)-pico)(CN)(4)](3-) and [MnN(eta(2)-pico)(CN)(3)](3-) complexes, respectively. Only the second steps could be spectrophotometrically observed and kinetically investigated. The first reaction is attributed to the rapid aqua substitution of [MnN(H2O)(CN)(4)](2), thermodynamically unfavored and too fast to observe by conventional rapid third generation stopped-flow techniques. The second, slower reaction is attributed to cyanido substitution, with overall formation rate constants (25 degrees C; k(1)'; M-1 s(-1)) and corresponding activation parameters (Delta H-k1'double dagger, kJ mol(-1), Delta S-k1"double dagger, J K-1 mol(-1)) for the following entering bidentate nucleophiles: pyridine-2-carboxylate: (1.15 +/-0.04) x 10(-3), 102 +/- 1, and 48 +/- 3; pyridine-2,3-dicarboxylate: (1.1 +/- 0.1) x 10(-3), 93 +/- 2, and 20 +/- 4; pyridine-2,4-dicathoxylate (8.5 +/- 0.5) x 10(-4), 123 +/- 5, and 115 +/- 14; pyridine-2,5-dicarboxylate: (1.08 +/- 0.04) x 10(-3), 106 +/-1, and 60 +/- 2. A dissociative activation for the cyanido substitution process is proposed.