Micron sized polymeric particles in custom designed geometries and with tunable chemical anisotropy are expected to enable a variety of new technologies in diverse areas such as photonics, diagnostics and functional materials. Current approaches for particle synthesis are either batch processes or flow-through microfluidic schemes that are based on two-phase systems, limiting the throughput, shape and functionality of the particles. We report a one-phase method called Stop Flow Lithography (SFL) that combines the advantages of microscope projection photolithography and polydimethylsiloxane (PDMS) microfluidics to continuously form arrays of morphologically complex or multifunctional particles down to the colloidal length scale. Acrylate based polymer chemistries can be used to synthesize virtually any two-dimensional extruded shape down to the colloidal length scale. Polymerization was also carried out across laminar, co-flowing streams to generate particles containing different chemistries, whose relative proportions could be easily tuned. Experimental details of the synthesis and modeling results on implementing SFL in microfluidics will be discussed. I will also present a simple model of the oxygen-inhibited photopolymerization reactions that occur inside microfluidic devices.