This work reports the cyclic voltammetric, modulatory effect on oxidative stress markers against radiation induced oxidative stress in E. coli bacteria and antiviral activities of two bischalcone derivatives (2E,5E)-2,5-bis(3-methoxy-4-hydroxy-benzylidene)-cyclopentanone (B1) and (2E,5E)-2,5-bis(4-fluorobenzylidene)-cyclopentanone (B2). The reducing ability of B1 and B2 was determined by cyclic voltammetry. The anodic peak current i pa and anodic peak potential Epa of B1 and B2 were −154.7, −99 μA, and −0.15 V, 0.0125 V, respectively. The low anodic current and low anodic peak potential imply the good reducing ability of the molecules. The radioprotective effect of bischalcones was studied by gamma radiation induced oxidative stress in E. coli K12 at 0.2 and 0.4 Gy. The bacteria samples treated with B1 and irradiated showed diminished level of TBARS, an oxidative stress marker. The levels of SOD and CAT antioxidant enzymes were brought to near basal level for B1 treated and irradiated bacteria with respect to the control. The protective effect of the bischalcone derivatives against radiation was further supported by determining colony forming units (CFU) of bacteria in pre- and post-irradiated samples. Further, B2 showed 73.69% of inhibition of buffalopox virus and camelpox virus.