This study delves into the promising realm of clean energy production through thermochemical conversion and chemical advancements. As the global demand for sustainable energy intensifies, exploring innovative technologies becomes imperative. The focus here is on harnessing the potential of thermochemical conversion, coupled with advancements in chemical processes. This dual approach holds significant promises for generating clean energy. The abstract underscores the critical role of these technologies in meeting escalating energy needs while shedding light on the advancements, challenges, and opportunities that pave the way for their successful implementation. Waste biomass represents an excellent bioresource that can be harnessed to produce numerous types of energy carriers, including bio-oil, bio-crude oil, biodiesel, syngas, biochar, and hydrogen. This article reviews the potential of various types of biomasses, including food waste, agricultural and forestry biomass, energy crops & oilseed crops, municipal solid waste, and animal manure, and also discusses the different types of reactors. In this review, comprehensively discusses all thermochemical methods for bio-oil production, including pyrolysis, gasification, and liquefaction. Each method is examined in detail, highlighting their respective processes, advantages, and challenges. Additionally, various types of reactors used in these methods are analyzed, emphasizing their roles and efficiencies in optimizing bio-oil yield and quality. Therefore, this review article will help in understanding the potentiality of waste biomasses for the production of clean energy via thermochemical techniques.