The interlayer aluminol surface of kaolinite has been modified by the reaction of methanol, at temperatures between 200 and 270 °C, with both the dimethyl sulfoside intercalate of kaolinite (Kao–DMSO) and the N-methylformamide intercalate of kaolinite (Kao-NMF). The product was a methoxy-functionalized organomineral material, which was resistant to thermal decomposition in both air and N₂ atmospheres up to temperatures > 350 °C, and also to water hydrolysis. Based on results from thermal analysis, IR analysis, NMR spectroscopy (¹³C CP MAS, ²⁹Si CP MAS and ²⁷Al MAS) and elemental analysis, a structural model has been proposed, in which every third interlayer surface hydroxy group on the aluminol surface of kaolinite has been replaced by a methoxide group. The methyl groups which point away from this surface are keyed into the (SiO)₆ macro-rings of the adjacent silicate surface, resulting in a non-centrosymmetric two-dimensionally ordered organomineral assembly.