Incorporation of a Lewis acidic BMes 2 (Mes = mesityl) moiety at the backbone of the imidazole ring was achieved by metal−halogen exchange procedure. Among them, two isomeric boron-phosphine functionalized imidazoles (3 and 6), monoboron-functionalized imidazoles (4 and 5), and its corresponding imidazolium salts were synthesized and thoroughly characterized. The solid-state structure of 3 reveals a dimeric B−N adduct that possesses six-membered [C−B− N] 2 ring, and 5 crystallizes as tetrameric B−N adduct that forms an interesting 16membered macrocycle, whereas 4 and 6 were obtained as monomeric BMes 2substituted imidazoles. 6 behaves as a P^N-type ligand upon the coordination with CuI to afford luminescent L 2 Cu 4 I 4 -type metal complexes (10 and 11) whose photophysical properties were also studied. The presence (in 10) and the absence (in 11) of BMes 2 made a remarkable impact on fluorescence emission causing shift from the green (10) to orange (11) region. The fluoride sensing properties of BMes 2 -containing imidazoles (4 to 9) were studied using UV−vis and fluorescence spectroscopy.