A series of novel pyrrolidine derivatives was designed, synthesized, and assayed to determine the derivatives' activity against matrix metalloproteinase-2 (MMP-2) and aminopeptidase N (APN)/CD13. Preliminary biological tests showed that most compounds inhibit MMP-2 in a highly selective manner compared to APN. Compounds 9d, 9e, and 9g had better inhibitory activity than LY52 and could be used as lead compounds in the future.