Two new low dimensional lead(Ⅱ) diiodide complexes with 1,10-phenanthroline-5,6-dione(Phendione), PbI2(Phendione)2(1) and PbI2(Phendione)(DMSO)2(2), have been synthesized by solution processes and structurally determined by X-ray diffraction method. Both compounds are mononuclear with the lead centers being in highly distorted octahedral environments. Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Theoretical calculations based on the DFT/B3 LYP level indicate that the introduction of electronic donating groups on the phenanthroline ring can improve the electron density of nitrogen atoms, and they can replace part of the bridged iodine atoms to lower the structural dimensions. Experimental band gaps of about 2.07 and 1.97 eV indicate their semiconductor nature. Two new low dimensional lead (Ⅱ) diiodide complexes with 1,10-phenanthroline-5,6-dione (Phendione), PbI2 (Phendione) 2 (1) and PbI2 (Phendione) (DMSO) 2 by solution processes and structurally determined by X-ray diffraction method. Both compounds are mononuclear with the lead centers being in highly distorted octahedral environments. Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Theoretical calculations based on the DFT / B3 LYP level indicate that the introduction of electronic donating groups on the phenanthroline ring can improve the electron density of nitrogen atoms, and they can replace part of the bridged iodine atoms to lower the structural dimensions. Experimental band gaps of about 2.07 and 1.97 eV their semiconductor nature.