Cytosolic phospholipase A2α (cPLA2α) is involved in eicosanoid biosynthesis and plays a key role in inflammatory diseases and stroke, but existing cPLA2α inhibitors have limitations in potency, specificity, and material characteristics. We searched for nonpeptide, low-molecular-weight cPLA2α inhibitors, identified two lead compounds (I and II) from our compound library with IC50 values of 1.5 µM and 1.7 µM, respectively. Through structure-activity relationship (SAR) studies using both enzyme assays and cell-based assays (to ensure specificity for arachidonic acid release and cell membrane penetration), we developed potent cPLA2α inhibitors with a 1,2,4-trisubstituted pyrrolidine framework (structures 1-4). These compounds feature ortho-substituted (benzoyl)benzoyl groups and 2,4-dioxo- (or 2-oxo-4-thioxo)thiazolidin-5-ylidenemethylphenyl groups. The most active compound, 4d, inhibited cPLA2α with an IC50 of 1.8 nM in enzyme assays and 22 nM in THP-1 cell assays (for arachidonic acid release), which was about 900-fold more potent than the lead compounds. These inhibitors specifically blocked cPLA2α-mediated arachidonic acid release without affecting downstream cyclooxygenase or 5-lipoxygenase, and showed no cytotoxicity even at 100 µM. They also reduced the production of eicosanoids (PGE2 and LTC4) in THP-1 cells, consistent with the role of cPLA2α in eicosanoid biosynthesis. Compared to existing inhibitors (e.g., AACOCF3), these pyrrolidine derivatives are extremely potent and selective. Thus, these compounds are valuable tools for elucidating the physiological role of cPLA2α and hold promise as therapeutic agents for inflammatory diseases and stroke.