A small library of novel quinoline derivatives containing different thioether substituents at position 4 have been synthesized and screened in murine hybridoma cell culture for their ability to enhance monoclonal antibody (mAb) production. From this set of compounds, four compounds have been discovered that enhanced immunoglobulin G (IgG) titer over negative control cultures due to an increase in specific productivity. These results demonstrate the utility of using organic synthesis and parallel ligand screening methods to discover novel cell culture additives that may be useful for increasing mAb yield in industrial biomanufacturing processes.