The title complex, [Cd（Pyphen）(1,4-BDC)（H2O）]·0.5Pyphen （1） （Pyphen=pyrazino[2,3-f][1,10]phenanthr-oline and 1,4-H2BDC=1,4-benzenedicarboxylic acid） has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. It crystallizes in orthorhombic, space group Pbcn with a=2.489 2（5） nm, b=0.967 88（19） nm, c=2.057 0（4） nm, V=4.955 9（17） nm3, Z=8, CdC29H18N6O4, Mr=642.89, Dc=1.723 g·cm-3, F（000）=2 576, μ（Mo Kα）=0.937 mm-1, R=0.039 6 and wR=0.102 6. The compound 1 exhibits one-dimensional chain structures, which are further stacked through π-π interactions to form supramolecular layers. Solid-state luminescent spectrum of the complex 1 indicates intense fluorescent emission.
