The invention relates to 5-oxo-3-pyrrolidinecarboxylic acid derivatives having the structural formula ##STR1## wherein X is selected from the group of ##STR2## R.sub.2 and R.sub.3 are each H or CH.sub.3, and R.sub.1 is H or a hydrocarbon radical having from 1 to 20 carbon atoms, which derivative compounds are suitable as monomers which can be homopolymerized or copolymerized to yield high molecular weight materials having many useful properties and applications, among which is their ability to form complexes with water insoluble molecules which are normally not complexible with similar type polymers.