A novel 3D coordination polymer, Zn-2(mu(2)-OH)(SIP)(DPP) (1), with mixed ligands of 5-sulfoisophthalate (SIP) and 1,3-di-4-pyridylpropane (DPP), has been hydrothermally synthesized and characterized. 1 contains an unusual 3D subnet with distorted (10,3)-d topology and left/right-handed helical channels. Second-harmonic-generation (SHG) measurements revealed that the material has a strong SHG response (similar to 2.5 times that of potassium dihydrogen phosphate (KDP)) and is phase-matchable. In addition, photoluminescent and thermogravimetric analysis were also performed on 1.