The kinetics of base hydrolysis of the low-spin iron(II)-diimine complex [Fe(fertri) 3 ] 2+ , where fertri=3-(2-pyridyl)-5,6-bis(2-furyl)-1,2,4-triazine, as a function of hydroxide concentration, solvent composition (water; aqueous MeOH), and pressure are reported. Rate constants are also reported for dissociation of the [Fe(fertri) 3 ] 2+ cation in 50-64% MeOH, determined from replacement of the fertri ligands by 1,10-phenanthroline. The reactivity of this fertri complex is compared with reactivities of a selection of other iron(II)-diimine complexes and, where possible, their ligand-sulfonated derivatives. The activation volume for base hydrolysis of [Fe(fertri) 3 ] 2+ is +10.7 cm 3 mol )1 , in 40% MeOH.