A series of indium(III) organophosphonates with coordinated 2,2′-bipyridyl and 1,10-phenanthroline ligands have been prepared and characterised. The bipyridyl and phenanthroline derivatives of indium(III) phenyl- and benzyl-phosphonates have a 1∶2∶1 molar ratio of metal∶phosphorus∶amine ligand, with proposed formulations In(O3PR)(O2P(OH)R)(C10H8N2)·H2O and In(O3PR)(O2P(OH)R)(C12H8N2)·H2O respectively (where R = C6H5 and CH2C6H5). Like the parent compounds, these adducts contain the organophosphonate ligand in both fully and partially deprotonated forms. In contrast, the bipyridyl and phenanthroline indium(III) methylphosphonates contain a 1∶1∶1 molar ratio of indium∶phosphorus∶amine, with proposed formulations In(OH)(O3PCH3)(C10H8N2) and In(OH)(O3PCH3)(C12H8N2)·2H2O respectively. Powder XRD measurements indicate that the bipyridyl phenylphosphonate and methylphosphonate compounds are layered, with interlayer spacing for the former (11.34 Å) reduced, and for the latter slightly increased (8.83 Å), relative to the parent indium(III) phenylphosphonate and methylphosphonate, respectively. The corresponding phenanthroline adducts of indium(III) phenylphosphonate and methylphosphonate do not possess layered structures. Both the bipyridyl and phenanthroline indium(III) benzylphosphonates are amorphous solids. FTIR, powder XRD, TGA and solid state 31P/13C MAS NMR data are presented.