Many mode-specific behaviors in the gas phase and at the gas-surface interface have been reported in the past decades. Infrared activation of a reagent vibrational mode is often used to study these reactions. In this work, an inexpensive and easily applied scheme using microwave irradiation is proposed for activating complex-forming reactions by transferring populations between closely spaced resonances. The important combustion reaction of H + O2 ↔ O + OH is used as a model system to demonstrate the feasibility of the proposed approach. The existence of a nonzero transition dipole moment matrix element between two highly excited resonance states separated by a small energy gap in the model system may allow one to use microwave irradiation to intervene and control the model reaction. The high energy resonance states of the model reaction can also release their energy by photon emission, which is in agreement with the experimentally observed chemiluminescence process.