Introduction: Imidic acid derivatives on dehydration under different conditions give corresponding imides and isoimides. A large number of applications of imides are known and plenty of methods to design them are well established. In comparison with imide, the isoimide chemistry is less explored and only limited isoimide chemistry is known. In 1955 Tsou et al reported the first isomaleimide synthesis using trifluoracetic anhydride as a dehydrating agent, recently isoimide have found applications in preparation of surfmers, novel polyimides, 4 novel polyisoimides, 5 pharmaceuticals, 6 spiro b-lactams, resins, 8 polyhydrazides, 9 herbicidal antidotes, 10 membranes, adhesives, diagnosis and cancer treatment and in vivo photodynamic therapy. Isoimides are useful in the detection and measurement of biological materials such as bacteria, enzymes and hormones. Presently isomaleimides have been synthesized from the corresponding maleamic acids by using (i) COCl2/Et3N, (ii) DCC, (iii) Ac2O/NaOAc, (iv) Page 2 of 9 CH3COCl/Et3N, 7 (v) EtOCOCl/Et3N, 7 (vi) (CF3CO)2O/Et3N, 17 (vii) ketenes 18 and (viii) 2chloro-1,3-dimethylimidazolinium chloride and cynuric chloride.