Interligand charge transfer is examined in the novel metallo-dithiolene complex MoO(SPh)(2)((i)Pr(2)Dt(0)) (where iPr(2)Dt(0) = N,N'-isopropyl-piperazine-2,3-dithione). The title complex displays a remarkable 70 envelope-type fold of the five-membered dithiolene ring, which is bent upward toward the terminal oxo ligand. A combination of electronic absorption and resonance Raman spectroscopies have been used to probe the basic electronic structure responsible for the large fold-angle distortion. The intense charge transfer transition observed at similar to 18 000 cm(-1) is assigned as a thiolate ? dithione ligand-to-ligand charge transfer (LL'CT) transition that also possesses Mo(IV) -> dithione charge transfer character. Strong orbital mixing between occupied and virtual orbitals with Mo(x(2)y(2)) orbital character is derived from a strong pseudo Jahn-Teller effect, which drives the large fold-angle distortion to yield a double-well potential in the electronic ground state.