7-(Benzyloxy)-1-(4-((2-oxo-1,2-dihydroquinolin-7-yl)oxy)butyl)quinolin-2(1H)-one 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.