Based on the above considerations, a new semi-rigid ligand, 4-((2-methyl-1 H-imidazol-1-yl) methyl)benzoic acid, was introduced to prepare new CPs with interesting structures and properties considering the following reasons, (1) whose parent structure (4-((1 H-imidazol-1-yl) methyl)-benzoic acid) has been proved it SB742457 can construct a variety of helical structures with good luminescent properties by others but their applications have not been developed . (2) One of our recent research interests has focused on the impact of functionalized ligands on the structure and properties of CPs. Meaningfully, methyl substituents on the central aromatic groups are assumed to improve photoluminescent properties of materials and the chemical stability of structures. Fortunately, three new 2D CPs containing chiral helical-layer, namely [ZnL2]n (1a and 1b) and [ML2]·(H2O)n (M=Zn (2), Cd (3)), have been obtained under hydro(solvo)thermal reaction. This work reports their crystal structures, luminescent properties and the unique application of 1 in detecting of Cu(II) ion in aqueous media and nitrobenzene. Furthermore, the possible detecting mechanism has been discussed.