Two new 2D polymers, thallium(I) hydrogensalicylate (1) and hydrogenphthalate (2), have been synthesized and characterized by elemental analysis, IR, 1H NMR and 13C NMR spectroscopy. The single-crystal X-ray data show the coordination number of the TlI ions of compounds 1 and 2 to be four and six with the environment TlO4 and TlO6, respectively. The arrangement of the O atoms suggests a gap in the coordination geometry around the thallium atoms in both compounds, due to a stereo-chemically ‘active’ electron lone pair of TlI. There is another interaction between the thallium atom and the carbon atoms of an aromatic ring in compound 1, giving a total hapticity of ten with the environment C6O4Tl.