The title complex [Mn(pht)(2)(phen)] (Hpht=5,5-diphenylimidazoline-2,4-dione, phen=1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR and X-ray diffraction single-crystal structure analysis. The compound crystallizes in the monoclinic system, space group C2/c with a=2.631 5(16) nm, b=0.9245(6) nm, c= 1.5508(10) nm, beta=116.231(7)degrees; V=3.384(4) nm(3), M-x=737.66, Z=4, F(000)= 1524, D-c= 1.448 g.cm(-3), mu=0.446 mm(-1), the final R=0.0699 and wR=0.195 3. The complex was valued for its antimicrobial activity against so-me bacteria in vitro. It was found to be active against the four test bacterial organisms. CCDC: 616309.