2,​2'-​[(4-​Butyl-​1,​3-​phenylene)​diimino]​bis-​2-​butenedioic Acid Tetramethyl Ester is an intermediate in synthesizing Bufrolin (B689405), an analog of Sodium Cromoglycate (C815000). It is a mast cell stabilizer drug and is shown to display agonism at either human or rat G protein-coupled receptor GPR35.