A series of mononuclear Ni-II and binuclear (NiNiII)-Ni-II macrocyclic complexes were investigated as functional models of the active site of [Ni-Fe]-hydrogenase. The electrocatalytic properties of the compounds were assessed and their efficiency was correlated with the availability of donor atoms in the structure of the macrocycle to accept the proton. The catalysts exhibited a regular activity for proton reduction. Redox levels and plausible electrochemical mechanisms for H-2 production are presented as well. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.