Two cadmium coordination polymers, namely [Cd(μ-dda)(H₂biim)]_n (1) and [Cd(μ₄-dda)(py)]_n (2) have been constructed hydrothermally using H₂dda (H₂dda = 4,4΄-dihydroxybiphenyl-3,3΄-dicarboxylic acid), H₂biim (H₂biim = 2,2΄-biimidazole), py (py = pyridine), and cadmium chloride at 160 °C. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses (TGA), and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both compounds crystallize in the monoclinic system, space group C2/c. Compound 1 discloses a 1D chain structure. Compound 2 features a 3D framework. The luminescent properties of compounds 1 and 2 were evaluated. Besides, the catalytic activities in the Knoevenagel condensation reaction of two compounds were investigated. Compound 1 exhibits an excellent catalytic activity in the Knoevenagel condensation reaction at room temperature.