7-(Phenylmethoxy)-2(1H)-quinolinone is an intermediate in synthesizing O-[4-((2-Oxo-1,2-dihydroquinolin-7-yl)oxy)butyl] Brexpiprazole (O855355), a derivative of Brexpiprazole (B677385) which is a drug candidate useful in treatment and prevention of mental disorders including CNS disorders.