A triazine-based fluorescent COF (MaTa-COF) was synthesized from inexpensive reactants. The obtained MaTa-COF has a large BET-specific surface area of 621.15 m2 g−1 and can be used as a highly sensitive Fe3+ fluorescent probe with a wide linear range of 0–250 μM and a low detection limit of 6.18 × 10−2 μM (Ksv = 2.34 × 108 M−1). Furthermore, the probe presented a good recyclability performance.
