Redox-active ligands bring electron- and proton-transfer reactions to main-group coordination chemistry. In this Forum Article, we demonstrate how ligand plc values can be used in the design of a reaction mechanism for a ligand-based electron- and proton-transfer pathway, where the ligand retains a negative charge and enables dihydrogen evolution. A bis(pyrazolyl)pyridine ligancl, (iPr)Pz(2)P, reacts with 2 equiv of AlCl3 to afford [((iPr)Pz(2)P)AlCl2(THF)][AlCl4] (1). A reaction involving two-electron reduction and single-ligand protonation of 1 affords [((iPr)HPz(2)P(-))AlCl2] (2), where each of the electron- and proton-transfer events is ligand-centered. Protonation of 2 would formally close a catalytic cycle for dihydrogen production. At -1.26 V versus SCE, in a 0.3 M Bu4NPF6/ tetrahydrofuran solution with salicylic acid or (HNEt3)(+) as the source of H+, 1 produced dihydrogen electrocatalytically, according to cyclic voltammetry and controlled potential electrolysis experiments. The mechanism for the reaction is most likely two electron transfer steps followed by two chemical steps based, on the available reactivity information. A comparison of this work with our previously reported aluminum complexes of the phenyl-substituted bis(imino)pyridine system ((I2P)-I-Ph) reveals that the pK(a) values of the N-donor atoms in (iPr)Pz(2)P are lower, which facilitates reduction before ligand protonation. In contrast, the (I2P)-I-Ph ligand complexes of aluminum are protonated twice before reduction liberates dihydrogen.