Controlling the chemical reactions through the selection of electronic resonance (metastable) pathways are proven to be a powerful method for molecular engineering. Recently, we have shown that site- and energy- specific one-step multi-bond breaking reactions are possible by using free-electron as a catalyst where the metastability of the system upon electron impact is responsible for the catalytic activity [1, 2]. In the first part of the talk, I will discuss on a few interesting, recent results of electron induced one-step multi-bond breaking reactions. I shall devote the second part of my talk for describing an interesting recent development in the area of calculating resonances using negative imaginary potentials (NIP) and its applications in chemistry [3]. I shall also present a computationally efficient ab initio quantum chemical method that can be used for generating an improved virtual orbital space for computing electronic resonance state.