Stereochemically Active and Inactive Lone Pairs in Two Room-Temperature Phosphorescence Coordination Polymers of Pb<sup>2+</sup> with Different Tricarboxylic Acids GaoXu-Sheng DaiHai-Jie DingMei-Juan PeiWen-Bo RenXiao-Ming 2019 Two new Pb<sup>2+</sup>-based coordination polymers (CPs), [Pb<sub>2</sub>(HBTC)<sub>2</sub>(DMF)] (<b>1</b>) and [Pb­(HPTC)] (<b>2</b>), have been synthesized under solvothermal condition; herein, H<sub>3</sub>BTC and H<sub>3</sub>PTC represent 1,3,5-benzenetricarboxylic acid and 2,4,6-pyridine tricarboxylic acid, respectively. Both <b>1</b> and <b>2</b> were characterized by microanalysis, infrared spectra (IR), thermal gravimetric analyses (TGA), and powder X-ray diffraction (PXRD) techniques. Single-crystal structural analysis indicates that <b>1</b> and <b>2</b> show different coordination sphere around Pb<sup>2+</sup> ions and distinct coordination frameworks. The I<sup>1</sup>O<sup>2</sup> type three-dimensional (3D) nonporous metal–organic framework forms in <b>1</b>, where the Pb<sup>2+</sup> ion shows holo-directed coordination geometry, while the I<sup>0</sup>O<sup>2</sup> type two-dimensional (2D) coordination polymeric layered structure forms in <b>2</b>, where Pb<sup>2+</sup> ion shows a hemidirected coordination sphere and the 6s<sup>2</sup> lone electron pair in Pb<sup>2+</sup> ion is stereochemically active. The two CPs emit intense and long-lasting greenish phosphorescence in air at room temperature, with absolute quantum yields of 1.2% for <b>1</b> and 4.7% for <b>2</b> and decay lifetimes of 0.73 ms for <b>1</b> and 1.52 ms for <b>2</b>.