An organic–inorganic hybrid molecule [(PyCH2NH3)6][Pb5I22]·3H2O (1) with a 2D inorganic layer was produced by reaction of 2-aminomethyl-pyridine with PbI2 in a concentrated HI aqueous solution. Compound 1 exhibited solid thermochromism showing a reversible color change from orange at room temperature to red at 80 °C, which was caused by the structural changes.
