In this study, we applied the unique transient ESFG to characterize charge transfer between heterojunction of monolayer MoS 2 and ruthenium(ii) polypyridyl complexes. We show that transient ESFG has a different sensitivity to trion dynamics compared to TA. The long-lasting bleach signal and lack of positive peaks in transient ESFG spectra of Ru-MoS2, in comparison to the one of pristine MoS 2 , strongly suggests the formation of CT-trions, resulting from the interfacial hole transfer from MoS 2 to the molecular adsorbates. The fast formation time (5.6 ps) showcases a very efficient CT-trion generation attributed to the reduced dimensionality, and that CT-trion dominates over regular trion at molecule-TMD interfaces. The dominance of CT trions opens the possibility to transfer many-body physics unique to TMD materials to the surface adsorbed molecules, leading to engineering surface molecules with unconventional catalytic performance. In return, molecular doping provides a new way to control many-body interactions of TMD. For example, by functionalizing specific areas of TMD with molecules, it can enable local electronic structures and dynamics engineering. Notably, not only the molecular dopant induced new interfacial species, it also altered the charge recombination dynamics, which can further affect the stability of TMD based optoelectronic devices.