Here, we specifically deal with transition metal intercalation in an isolated, freestanding triazine-benzene-boroxine 2D COF bilayer, a material which-to the best of our knowledge-has not been conceptualized in the past. Our main hypothesis is that by controlling the intercalated d-block elements and concentrations, we will be able to modify their interlayer interactions (by promoting interactions between the COF π-orbitals and TM d-orbitals), which can lead to fine-tuning their electronic and magnetic behavior. Such changes include, for example, modifying the 2D COF's natural insulating behavior to that of a semiconductor, by promoting the appearance of available states near the Fermi level via COF p-orbital and TM d-orbital interactions. This is illustrated in Figure . Furthermore, electron confinement in two spatial dimensions is known to drastically change the electronic properties of materials when they are reduced from bulk to 2D. Therefore, the electronic properties of these bilayer 2D COFs are expected to be drastically different from their previously-explored bulk counterparts. 2 Results & Discussion