In this method, the extent of aryl bromide consumption reflects the quality of mixing at the lithiation stage at a given flow rate. Therefore, the lithiation in flow of 4-bromoanisole 1 (selected as our test substrate because of its slow metalation rate ) and its trapping by aldehyde 2 to form alcohol 3 (the desired product), or conversion into anisole 4 was studied at constant (where possible) residence time while varying flow rate and mixer type. In this way, the presence of alcohol 3 and anisole 4 in the generated output streams would serve as markers of successful lithiation, whereas increased amounts of anisole 4 relative to alcohol 3 would suggest: instability of the lithiate under the experimental conditions, poor reagent solution quality or ineffective reagent mixing at the secondary trapping stage, leading to incomplete consumption of the lithiate prior to a protic quench. By-product 5 was expected and observed in all runs, due to the molar excesses of HexLi and aldehyde 2 used. Through this arm of the work, we hoped to obtain data to inform the design of a general-purpose, cost-effective, low-volume, lithiation-trapping reactor capable of successfully processing both reactive and unreactive aryl halides.