Perturbation-facilitated optical-optical double resonance spectroscopy has been applied to study the h0(u)(-)(P-3(1)) and H1(u)(P-3(1)) ion-pair states of I-2 correlating with I-(S-1)+I+(P-3(1)). The intermediate states used were the g/u parity mixed states found in the B (3)Pi(0(u)(+))-X (1)Sigma(g)(+) absorption spectrum near the dissociation limit. We identified several B (3)Pi(0(u)(+))similar to(3)Pi(0(g)(-)) coupled states by hyperfine interactions for the first time. These states had the 0(u)(+) and 0(g)(-) double-faced character and facilitated to combine the X (1)Sigma(g)(+) ground state with the h0(u)(-)(P-3(1)) state in the (1+1) photon excitation scheme following the optical selection rules for one-photon transition. We also accessed the H1(u)(P-3(1)) state through the B (3)Pi(0(u)(+))similar toc1(g) mixed state, and elucidated the heterogeneous coupling between the h0(u)(-)(P-3(1)) and H1(u)(P-3(1)) states. Our analyses covered the region of about 48 200 to 50 300 cm-1, and gave the molecular parameters of the h0(u)(-)(P-3(1)) state valid for v=0-17 and those of the H1(u)(P-3(1)) state for v=0-20. The (3)Pi(0(g)(-)) state used as an intermediate state was analyzed through the dispersed h0(u)(-)(P-3(1))-(3)Pi(0(g)(-)) emission in conjunction with the Franck-Condon factor calculations, and the principle spectroscopic constants of the (3)Pi(0(g)(-)) state were reported.