Polyimide, a commercial organic polymer widely used as electronics coating, is found to have excellent electrochemical catalytic performance in water splitting and N2 fixation recently. Our exciting results are introduced as following two parts: 1.The exploitation of metal-free organic polymers as electrodes for water splitting reactions is limited by their presumably low activity and poor stability, especially for the oxygen evolution reaction (OER) under more critical conditions. Now, the thickness of a cheap and robust polymer, poly(p-phenylene pyromellitimide) (PPPI) was rationally engineered by an in situ polymerization method to make the metal-free polymer available for the first time as flexible, tailorable, efficient, and ultra-stable electrodes for water oxidation over a wide pH range. The PPPI electrode with an optimized thickness of about 200 nm provided a current density of 32.8 mA cm-2 at an overpotential of 510 mV in 0.1 mol L-1 KOH, which is even higher than that (31.5 mA cm-2) of commercial IrO2 OER catalyst. The PPPI electrodes are scalable and stable, maintaining 92% of its activity after a 48-h chronoamperometric stability test. 2.Production of ammonia is currently realized by the high pressure-high temperature Haber–Bosch process, while electrochemical N2 fixation under ambient conditions is recognized as a promising green substitution in the near future. Lack of efficient electrocatalysts for selective fixation and reduction of dinitrogen remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date, as the process is theoretically considered not to be energetically feasible. In this work, we boost the N2 reduction reaction (NRR) catalytic activity of Cu nanoparticles, which originally exhibited negligible NRR activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide (PI) support which retards the hydrogen evolution reaction (HER) process in basic electrolytes and facilitates the N2 fixation to afford the electrochemical NRR process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive NRR catalysts with high selectivity and activity.