The optimal synthesis of advanced nanomaterials with numerous reaction parameters, stages, and routes, poses one of the most complex challenges of modern colloidal science, and current strategies often fail to meet the demands of these combinatorially large systems. In response, we present an Artificial Chemist: the integration of machine learning-based experiment selection and high-efficiency autonomous flow chemistry. With the self-driving Artificial Chemist, we autonomously synthesize made-to-measure inorganic perovskite quantum dots (QDs) in flow, and simultaneously tune for their quantum yield and composition polydispersity at target bandgaps, spanning 1.9 eV to 2.9 eV. Utilizing the Artificial Chemist, eleven precision-tailored QD synthesis compositions are obtained without any prior knowledge, within 30 h, using less than 210 mL of total starting QD solutions, and without user selection of experiments. Using the knowledge generated from these studies, we then pre-train the Artificial Chemist to use a new batch of precursors and further accelerate the synthetic path discovery of QD compositions, by at least two-fold. The knowledge transfer strategy further enhances the optoelectronic properties of the in-flow synthesized QDs (within the same resources as the no-prior knowledge experiments) and mitigates the issues of batch-to-batch precursor variability, resulting in QDs averaging within 1 meV from their target bandgap.