SYNOPSISThe effect of the solvent 1-methyl-2-pyrrolidinone ( N M P ) on the curing of polyimide resins synthesized from pyromellitic dianhydride ( PMDA) and 4,4'-oxydianiline (ODA) has been investigated. Three polyimide precursors, i.e., the polyamic acid ( PAA) , with ond step involves the dehydrative cyclization of the PAA ( imidization ) to give rise to the polyimide (PI).This description fails to disclose the complexity and specific features of the two-step method. Important factors that affect the ultimate properties of a polyimide resin may include the nature of solvent-PAA interaction, the imidization reaction, and the side reactions accompanying these processes such as the reversible anhydride formation.The solvent-PAA interaction has been well established by various author^.^-^ Worthy of note is the study of a low-molecular-weight polyimide model compound by Brekner and Feger.3 They revealed the existence of 4 / 1 and 2 / 1 molar complexes between the solvent 1-methyl-2-pyrrolidinone ( N M P ) and the diamic acid synthesized from pyromellitic