The crystal structures of [Zn(dnb)2]n and [Co(dnb)2(H2O)4]·4H2O (dnb = 3,5-dinitrobenzoate) have been determined based on single-crystal X-ray diffraction data. [Zn(dnb)2]n crystallizes in the trigonal space group P 3 1 2 1 , a 11.042(4), b 11.042(4), c 11.498(5) A, Z 3, R1 0.0230, wR2 0.0554. The zinc complex features infinite chiral chains in the solid, in which each pair of adjacent tetrahedrally coordinated zinc atoms are bridged by two dnb ligands, exhibiting powder second harmonic generation efficiency 0.34 times that of urea. [Co(dnb)2(H2O)4]·4H2O crystallizes in the triclinic space group P1, a 7.169(6), b 11.672(7), c 14.951(7) A, a 102.940(10), b 98.36(10), g 92.390(10)˚, Z 2, R1 = 0.0417, wR2 0.0966. The cobalt complex exists as mononuclear molecules in the lattice, in which the cobalt atom is coordinated by two monodentate dnb ligands and four aqua ligands in an octahedral arrangement.