Abstract: Disclosed herein is a process for preparing a linear hydroxyaryloxy-functional polydiorganosiloxanes having controlled structures. The process includes the step of reacting a linear ?,?-bisacyloxypolydiorganosiloxane with at least one bisphenolic compound, or hydroxy-functional oligomer thereof, in such a molar ratio that the phenolic groups in the bisphenolic compound or the hydroxy-functional oligomer thereof to the acyloxy groups in the ?,?-bisacyloxypolydiorganosiloxane is less than 2.0. Also disclosed are hydroxyaryloxy-functional polydiorganosiloxanes produced from the process and the polysiloxane/polyorgano block copolymers made using the hydroxyaryloxy-functional siloxanes.