Covalent immobilization using a "click" reaction for a cobalt complex (top, Reproduced with permission from Ref. 66. Copyright 2012 American Chemical Society) and iron complex (bottom, Reproduced with permission from Ref. 94. Copyright 2019 American Chemical Society). Examples of CO2 reduction, oxygen evolution and reduction show that immobilization generally introduces a high activity to the molecular electrocatalyst due to a facile and efficient electron transfer from the electrode support to the catalyst through covalent or non-covalent interactions. A highly conjugated molecular linker also results in a strong electron coupling between the molecular moiety and the electrode than other methods. However, non-covalent interactions such as π-π stacking, depending on the catalytic system, may still exhibit higher activity than covalently ligated analogues. A comparison between a short conjugated linker, a long alkene linker, π-π interactions, and simple adsorption of cobalt complexes on carbon nanotubes in electrocatalytic water splitting reveals that the short conjugated linkage surpasses π-π interactions and the long alkene linker in electron transfer ability. In addition, those three immobilization methods afford a stable catalytic material, which could stabilize active intermediates during the reaction and showcase a long lifetime with minimal catalyst aggregation.