This article explains unique photochemical reaction named nonadiabatic photochemical process. First, the experimental results of the deposition of Zn nano-dots using the nonadiabatic optical chemical vapor deposition are reviewed. Their deposition rate dependences on the incident optical power are explained by the excitation of the molecular vibrational state by the dressed photon. Second application of the nonadiabatic photochemical reaction to the photolithography is reviewed using fabrication of Fresnel zone plates as an experimental example.