Lithium disilicate (Li2Si2O5) coatings were prepared by spin-coating alkoxide solutions on to substrates [Si, SiO2, polycrystalline (poly) Si, sapphire] and heating isothermally at 500-600 degrees C. The effects of solution chemistry, coating thickness and substrate type on crystallization behaviour and microstructure development were investigated using atomic force microscopy, X-ray diffraction and transmission electron microscopy. Amorphous dried coatings began to crystallize into Li2Si2O5 at 500-550 degrees C. Coatings prepared on Si substrates (with a thin native oxide) using Li-Si methoxyethoxide solution crystallized into microstructures with large grain sizes (ca. 2-5 mu m diameter) as compared with the coating thickness (<0.3 mu m). Nucleation rate in these coatings could be increased (and hence transformation rate increased and grain size decreased) by : (1) adding H2PtCl6 to the solution to act as nucleation agent; (2) increasing the thickness of the coating; or (3) using a crystalline substrate (sapphire or poly Si). Coatings prepared using Li-Si ethoxide solution had fine-grained microstructures (less than or equal to 0.5 mu m diameter) for all substrates. Chemical heterogeneity in the ethoxide system may have increased nucleation rate. Nucleation rate in th is system could be decreased by using partially hydrolysed tetraethylorthosilicate as the Si precursor. The relationship between solution chemistry and microstructure was used to tailor microstructures in multilayer coatings.