The COF, HAT-DAB synthesis was optimized by using re-crystalized HAT-CN and polymerisation with DAB through SNAr type reactions under refluxing conditions in N-Methyl-2-pyrrolidone (NMP) as solvent shown in the scheme (Figure ). A ferrous sulphate (FeSO4) trap was used for the liberated hydrogen cyanide (HCN) in the reaction, and it is also used to indirectly confirm the formation of the COF. The generated HCN gas reacts with FeSO4 in the trap solution to form iron cyanide complex and a colour change from yellow to green (Figure ) is observed after few hours of reaction. The IR of the green precipitate when compared to FeSO4 also shows a clear C≡N stretch (Figure ). The formation of the COF material is initially hinted by its insolubility in common solvents, as well as in strong acids and bases (Figure ).