PURPOSE: To obtain the titled substance in high yield without producing polymeric by-products, by heating maleic anhydride and an aromatic or aliphatic diamine in an organic solvent in the presence of an ion-exchange resin at a temperature within a specific range to effect dehydrative cyclization reaction.

CONSTITUTION: The titled substance can be produced by using maleic anhydride and an aromatic or aliphatic diamine at a molar ratio of 1:(0.4W0.6) and heating the components at 50W160°C in an organic solvent (preferably a mixture of an aromatic hydrocarbon and an aprotic polar solvent) in the presence of an ion-exchange resin (preferably strongly acidic, weakly acidic or weakly basic ion exchange resin) to effect the dehydrative cyclization of the components. As an alternative method, the objective substance is produced by reacting maleic anhydride with an aromtic or aliphatic diamine to obtain a bismaleamic acid and subjecting the product to dehydrative cyclization similar to the above process without separating the amic acid from the reaction system.

EFFECT: The catalyst can be regenerated.

USE: Raw material for functional polymers and intermediate for pharmaceuticals and agricultural chemicals.