The disclosure relates to a microfluidic system for the screening of polymorphs, morphology, and crystallization kinetics under well-mixed, continuous-flow at controlled supersaturations. The disclosure also relates to a method for screening crystalline polymorphs and morphology, and crystallization kinetics. The microfluidic system includes a microfluidic chamber having one or more inlets, a passive mixing zone, and a trap zone. The passive mixing zone promotes mixing of solvent, solute, and optionally antisolvent under stable, controlled levels of supersaturation. The trap zone similarly has stable, controlled levels of supersaturation and correspondingly low velocity to retain solute crystals formed in the trap zone for time-dependent evaluation.