The acid-catalyzed interconversion of cyclic anhydride and di-acid or ester-acid groups within polymers rich in vicinal dicarboxyls, such as are found in many copolymers of maleic anhydride, is the basis for a new kind of resist chemistry that is not susceptible to many of the problems found in existing chemically-amplified resists that are based on acid-cleavable carbonate, ester, ether or acetal groups. With sufficient vicinal dicarboxyls, or other hydrophilic contribution, the hydrated forms of these relatively UV- transparent polymers dissolve in relatively polar solvents, and even (in the extreme) in neutral water, in which the dehydrated (i.e. anhydride) forms are insoluble. Combining with water-dispersible diphenyliodonium initiator gives chemically-amplified resists that can thus be spin-coated, then (according to sequence of heat, humidity and UV radiation) developed into an image of either positive or negative tone, and eventually stripped from substrate--each step using only plain neutral water as the processing liquid. Plasma etch resistance was evaluated for both hydrated and dehydrated forms of several of these polymers, including some with polycyclic comonomers: in general, a larger number of cycles in the structure improved the etch resistance, even (surprisingly so) when such were oxygen- containing rings of the cyclic anhydride functionalities. Such reactive films would also lend themselves well to incorporation of a variety of organic and inorganic species for `functional patterning', and oxygen plasma development.