One of the groups of organic polymers that is known for its both excellent permanent porosity and crystallinity is called covalent organic frameworks (COFs). These polymers can be synthesized and extended in two-dimensional (2D) or three-dimensional (3D) forms based on the reaction conditions and their precursors through condensation reactions. Numerous papers have been reported about designing electrocatalysts that are based on COFs in the field of oxygen evolution, oxygen reduction, hydrogen evolution, and CO2 reduction reactions as their applications so far. In this chapter, engineering COFs for preparing electrocatalysts that are appropriate for the above-mentioned applications is explained in detail, especially for electrocatalytic oxygen evolution reactions (OER). The developments of this kind of reaction are discussed and also the relation between COFs’ structures and oxygen evolution reaction is studied to consider its effect on electrocatalytic performance.