A new microporous europium-containing metal–organic framework [Eu₂(μ₂-pzdc)(μ₄-pzdc)(μ₂-ox)(H₂O)₄]·8H₂O (1) (H₂pzdc = 2,5-pyrazinedicarboxylic acid, H₂ox = oxalic acid) has been hydrothermally synthesized via an unprecedented in situ formation of 2,5-pyrazinedicarboxylate (pzdc) and oxalate (ox) ligands. Structure 1 was characterized by both single-crystal and powder X-ray diffraction analysis. It can be described as a 4-connected binodal Moganite network with the Schläfli symbol of (4·6⁴·8)₂(4²·6²·8²), which exhibits a reversible and highly selective sensing function with respect to acetone.