When a solution containing xylose and L-lysine is heated under weakly acidic conditions, it turns brown by the Maillard reaction. We isolated here two novel yellow compoundsfrom a heated solution containing xylose and lysine, and identified pyrrolyl-methylidene-pyrrolone derivatives named dilysyldipyrrolones A and B. Their chemical structures were elucidated by instrumental analyses as 6-[[1-[(S)