Coordination polymers constructed from conjugated organic ligands and metal ions with a d10 electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A ZnII‐based coordination polymer, namely poly[aqua(μ6‐biphenyl‐3,3′,5,5′‐tetracarboxylato)(μ2‐4,4′‐bipyridine)dizinc(II)], [Zn2(C16H6O8)(C10H8N2)(H2O)2]n or [Zn2(m,m‐bpta)(4,4′‐bipy)(H2O)2]n, was synthesized from a mixture of biphenyl‐3,3′,5,5′‐tetracarboxylic acid [H4(m,m‐bpta)], 4,4′‐bipyridine (4,4′‐bipy) and Zn(NO3)2·6H2O under solvothermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis, and features a μ6‐coordination mode. The ZnII ions adopt square‐pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn2(COO)2] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m‐bpta)4− ligands to produce a two‐dimensional grid‐like layer that exhibits a stair‐like structure along the a axis. Adjacent layers are linked by 4,4′‐bipy ligands to form a three‐dimensional network with a {44.610.8}{44.62} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe3+ ions. In a ZnII‐based coordination polymer synthesized from a mixture of biphenyl‐3,3′,5,5′‐tetracarboxylic acid, 4,4′‐bipyridine and Zn(NO3)2·6H2O under solvothermal conditions, the ZnII ions adopt square‐pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn2(COO)2] units. These units are crosslinked by tetracarboxylate ligands to produce a two‐dimensional grid‐like layer that exhibits a stair‐like structure along the a axis. The luminescence sensing results indicate a highly selective and sensitive sensing for Fe3+ ions. [ABSTRACT FROM AUTHOR]