Аннотация:A new derivative of 4-methoxy-1,8-naphthalimide containing a chelating motif of mono-N-nitrilotriacetic acid demonstrates an effective coordination with Ni2+ in a HEPES-buffer solution resulting in the formation of 1 : 1 ligand–metal complex, which demonstrates the ability to stain His-labeled proteins on gel after electrophoresis to make the analysis and purification of proteins more convenient.