Figure indicates that most peaks in the spectrum of the COF-1 structure can easily be assigned to the phenyl and boroxine contributions. Starting with the area highlighted in blue, we know from normal mode analysis that the peak at 3150 cm -1 originates from the C-H stretches. We can now also confirm with the AIMD-based approach that this band is indeed associated with the phenyl fragments. Similarly, the peak at 1600 cm -1 (area highlighted in green) clearly originates from the phenyl fragments. Normal mode analysis also shows that this band belongs to the aromatic C-C stretches.