A number of fairly hydrophilic microporous poly{N,N-dimethylacrylamide-methylenebisacrylamide} (cross-linking degree from 1 to 8%) have been examined with two conceptually and experimentally quite independent techniques that are able to provide information on the macromolecular structure and chemical accessibility of these materials in the swollen state. Electron spin resonance spectroscopy (ESR) and inverse steric exclusion chromatography (ISEC) gave quite consistent results in water, which are interpreted on the basis of a physico-mathematical model that fits the experimental data nicely. The resulting equation appears as a promising tool in the design of macromolecular materials for chemical and catalytic applications.