A highly sensitive and selective naked-eye probe, 2,5-bis[3-benzyl-2-methylbenzothiazole]-croconaine (BMC) for sensing of Fe3+ was synthesized and characterized. The BMC can selectively recognize Fe3+ among the test cations (Ni2+, Mg2+, Cu2+, Ca2+, Na+, K+, Cr3+, Ag+, Ba2+, Zn2+, Pb2+, Al3+, Fe3+, Cd2+, Co2+) in DMF/H2O (4:1, v/v). The binding constant of BMC-Fe3+ was evaluated by using Benesi-Hildebrand plot. Simultaneously, the binding mode of BMC-Fe3+ was supporting by Job's plot, ESI-MS, FT-IR and 1H NMR. Correspondingly, the morphology of chelate complex was investigated by FESEM. Moreover, Fe3+ and EDTA could be employed as inputs and the fluorescence emission intensity which was 816 nm as output so that a molecular logic gate could be realized.