Microporous organic polymers (MOPs) are materials made from organic monomers that have a pore width smaller than 2 nm. Due to their high porosity and diversity of functional group, MOPs have potential in broad ranges of applications. As well as absolute surface area, the functional groups also play an important role in the design and synthesis of materials for desired utilisations. In this work, we demonstrate strategies to synthesise functionalised networks to be utilised as sorbents. The focus is on hypercross-linked polymers (HCPs) and conjugated microporous polymers (CMPs), which are amorphous networks and subclasses of MOPs. Different strategies including copolymerisation, post-cross-linking of functionalised linear polymer chains, and post-synthetic modification (PSM) were found able to incorporate different functional groups into the networks. The structures and properties of the networks could be fine tuned. The networks were investigated for applications in CO2 capture and separations as well as molecular imprinting polymers (MIPs).