Metal alkoxides are hydrolyzed and the hydrolysates are modified with a coupling agent containing alkyl chains. The modified uni-hydrolysates, prepared using each of the alkoxides of Ti, Fe, Al, and Zr, and the modified bi-hydrolysates, prepared using two alkoxides consisting of a given alkoxide as one and Ti or Al alkoxide as the other, are dispersible homogeneously into organic solvents. Organic solutions of the modified bi-hydrolysates show spectral changes with light irradiation when they are prepared using Ti alkoxide. The spectral changes are due to intra- and/or inter-particulate electron transfer from photogenerated Ti3+ to other metal atoms in the hydrolysates. The electron transfer is efficient, which can be explained in terms of extremely fine particle size of the modified hydrolysates.