We investigated the electronic properties of a single crystal of metallic pyrochlore iridate Bi 2 Ir 2 O 7 by means of infrared spectroscopy. Our optical conductivity data show the splitting of t 2g bands into J eff ones due to strong spin-orbit coupling. We observed a sizable mid-infrared absorption near 0.2 eV which can be attributed to the optical transition within the J eff,1/2 bands.More interestingly, we found an abrupt suppression of optical conductivity in the very farinfrared region. Our results suggest that the electronic structure of Bi 2 Ir 2 O 7 is governed by the 2 strong spin-orbit coupling and correlation effects, which are prerequisite for theoretically proposed non-trivial topological phases in pyrochlore iridates.PACS number: 78.20.-e, 71.30.+h, 71.20.-b 3