Parallel-synthesis of biomolecular components offers a rapid path to constructing multiple gene networks that behave as predicted by in silico modeling. Here we describe the synthesis and screening steps to produce a component library, using the example of repressible promoters for S. cerevisiae. Regulatory promoters such as these are crucial components in genetic networks and quantified variability in input and output can be used to design diverse networks. The parallel synthesis approach described here is not limited to promoters or S. cerevisiae and should be broadly applicable to all biomolecular components with protocol adaptations.