A method of making dialkyl-, diaryl-, or alkylaryl-dihalosilanes with a high degree of selectivity in a Grignard coupling reaction, the method comprising the steps of: providing a reactor, the reactor selected as one from the group of a plug flow reactor, a continuous tube reactor, a piston flow reactor, and more than one continuous stirred tank reactor (CSTR) connected in series; providing a hydrocarbon solvent stream at a predetermined flow rate to the reactor; providing an alkyl- or aryl-trihalosilane stream at a predetermined flow rate to the reactor; providing a Grignard reagent stream comprising an alkyl- or aryl-magnesium halide at a predetermined flow rate to the reactor; allowing the solvent stream, alkyl- or aryl-trihalosilane stream, and Grignard reagent stream to combine to form a combined reactant stream; wherein the flow rate of the solvent stream, alkyl- or aryl-trihalosilane stream, and the Grignard reagent stream are selected so that the mass ratio of the alkyl- or aryl-trihalosilane to the Grignard reagent in the combined reactant stream is greater than or equal to 1.5:1 and the mass ratio of the solvent to the Grignard reagent in the combined reactant stream is greater than or equal to 3:1; allowing the combined reactant stream to react at a temperature from 10°C to 80°C to form a product mixture comprising R 2 SiX 2, R 3 SiX, and a salt, wherein each R is independently selected to be an alkyl or aryl group, X is a halogen group, and the mass ratio of R 2 SiX 2 to R 3 SiX in the product mixture is greater than 7:1; and optionally, collecting the product mixture, wherein the combined reactant stream has a flow rate that is predetermined based on the size of the reactor such that the average amount of time that the combined reactant stream resides in the reactor is less than 30 seconds. providing a reactor, the reactor selected as one from the group of a plug flow reactor, a continuous tube reactor, a piston flow reactor, and more than one continuous stirred tank reactor (CSTR) connected in series; providing a hydrocarbon solvent stream at a predetermined flow rate to the reactor; providing an alkyl- or aryl-trihalosilane stream at a predetermined flow rate to the reactor; providing a Grignard reagent stream comprising an alkyl- or aryl-magnesium halide at a predetermined flow rate to the reactor; allowing the solvent stream, alkyl- or aryl-trihalosilane stream, and Grignard reagent stream to combine to form a combined reactant stream; wherein the flow rate of the solvent stream, alkyl- or aryl-trihalosilane stream, and the Grignard reagent stream are selected so that the mass ratio of the alkyl- or aryl-trihalosilane to the Grignard reagent in the combined reactant stream is greater than or equal to 1.5:1 and the mass ratio of the solvent to the Grignard reagent in the combined reactant stream is greater than or equal to 3:1; allowing the combined reactant stream to react at a temperature from 10°C to 80°C to form a product mixture comprising R 2 SiX 2, R 3 SiX, and a salt, wherein each R is independently selected to be an alkyl or aryl group, X is a halogen group, and the mass ratio of R 2 SiX 2 to R 3 SiX in the product mixture is greater than 7:1; and optionally, collecting the product mixture, wherein the combined reactant stream has a flow rate that is predetermined based on the size of the reactor such that the average amount of time that the combined reactant stream resides in the reactor is less than 30 seconds.