Various immobilization methods on carbon-based electrodes (e.g., graphene and carbon nanotubes) have been reported and categorized into non-covalent or covalent methods and periodic doping modification methods. The coupling of organometallic complexes with carbon-based electrodes combines the stability and conductivity of carbon electrodes with the high activity and selectivity of metal complexes. Figure depicts common strategies for functionalizing electrode surfaces represented by carbonbased electrodes. Polymer coating, adsorption, and non-covalent and covalent methods have been widely applied. To implement certain specific functionalities onto the surface via the covalent immobilization method, the surface often needs pretreatment. We will focus on the non-covalent and covalent methods for surface functionalization as they are feasible and allow for various linkages and structural diversity of molecular catalysts. The periodic doping method will not be included in this review as it is not suitable for anchoring functionalities. Non-covalent methods involve nonbonding interactions such as van der Waals forces, electrostatic interactions, hydrogen bonding, and π-π stacking interactions. Among these methods, π-π stacking between a ligand and an electrode represents a straightforward strategy of immobilizing aromatic compounds onto the electrode surface (Figure ). Applications of immobilized molecular electrocatalysts via non-covalent methods in reactions related to energy conversion such as CO2 reduction and oxygen evolution reaction (OER) have been well-studied and summarized. Despite the convenience of the non-covalent immobilization method, challenges remain in reducing catalyst leaching and aggregation to optimize the performance and durability of the electrocatalytic system.