When gaseous iodine was admitted into the NCl3 autodecomposition flame, intense I(5 P-2(1/2)) -> I(5 P-2(3/2)) emission was observed owing to direct pumping of iodine atoms by NCl3 flame. It is found that the chemical environment of NCl3 flame is benign for I(5 P-2(3/2)). The mechanisms of I(5 P-2(1/2)) production in the NCl3/I-2 reactive gas flow are discussed for the first time. It is believed that Frank-Condon favored E-E energy transfer from Cl-2(B) to I(5 P-2(3/2)) and the nearly resonant V-E energy transfer from Cl-2(X, v = 15) to I(5 P-2(3/2)) respond for the production of excited state iodine atoms.