A new Zn(II)-based coordination polymer (CP) having the composition [Zn3(L)2(phen)2] (1) (H2L=3,3ʹ-(1,4-phenylene-bis-(methyleneoxy)dibenzoic acid, phen= 1,10-phenanthroline) has been synthesized using mixed ligand strategy under solvothermal conditions. 1 has been characterized by microanalyses, FTIR, UV–Vis spectroscopy, and single X-ray diffraction technique. The structural analyses show that 1 possess 2D supramolecular framework that is formed by weak interactions between its chains. The optical band of 2.7 eV suggests that 1 possesses semiconducting property. 1 has been used as photocatalyst to photodegrade varied antibiotics, amongst which it exhibits best photodegradation of the nitrofurazone antibiotic. A plausible photocatalytic degradation pathway has been proposed by radical tapping experiments and theoretical calculations.