Compound for use as a solid electrolyte or proton conductor in a membrane electrode assembly in fuel cells

A compound useful for a proton conductor which is obtained through sulfonation followed by sol-gel reaction, or through sol-gel reaction followed by sulfonation of a compound of the following formula: wherein A is meaogen-containing organic group; R is H, alkyl, aryl or silyl; R is alkyl, aryl or heterocyclic; ml is 1-3; L is single bond, alkylene, -O-, -CO-, or a combination thereof; Ar is arylene or heteroarylene having electron-donating group; Y is polymerizable group; n11 is 1-8; n12 is 1-4; and s1 is 1 or 2.