Novel isocyanato-azetidinedione compounds are provided which have the formula ##STR1## wherein R and R.sub.1 can be independently selected from hydrogen and hydrocarbyl or can be joined together and along with the carbon to which they are attached represent a cycloalkane residue having 4 to 6 ring carbon atoms, y is an integer from 1 to 7 and X is a hydrocarbon radical having a valency of y plus one.The monoisocyanate compounds are used as intermediates to provide further novel azetidinedione containing derivatives in the form of azetidinedione-isocyanurates (II) and azetidinedione-urethanes (III).All three classes of compounds can be employed as acid scavenging agents for stabilizing various kinds of halogenated polymer systems. Notably, (I) and (III) form highly useful polyamide-polyureas and polyamide-polyurethanes respectively by reaction with organic polyamines.