The resistance of bacteria against ${eta}$-lactam antibiotics is mainly caused by the production of ${eta}$-lactamase enzymes. ${eta}$-Lactamase inhibitors are used in combination with known antibiotics to overcome the growing problem of bacterial resistance. We prepared 6-(thienylmethylene)penam sulfones for the development of potent ${eta}$-lactamase inhibitors and evaluated their ${eta}$-lactamase inhibitory activities.