Thermochemical conversion offers a promising route for waste reduction and the recovery of potentially valuable chemicals from heterogeneous feedstocks. This study combines a focused review of reported pyrolytic product distributions with an ongoing experimental investigation of selected waste-derived and lignocellulosic feedstocks. The review examines how feedstock characteristics and pyrolysis temperature influence the formation of major chemical families, including oxygenated compounds, aromatic compounds, hydrocarbons and nitrogen-containing species. Guided by this literature-derived framework, the selected feedstocks are being characterized by pyrolysis-gas chromatography-mass spectrometry over a temperature range of 500-800 °C. The resulting chromatographic profiles will be used to identify major volatile products, evaluate temperature-dependent changes in product distribution and chemical complexity, and distinguish composition-related differences among the feedstocks. Particular attention is given to differences in the thermal decomposition behavior of heterogeneous waste-derived materials and lignocellulosic biomass, as well as to temperature ranges associated in previous studies with the formation of potentially valuable chemical fractions. By integrating evidence from the literature with systematic experimental fingerprinting, this work aims to establish a comparative framework for interpreting feedstock-dependent pyrolysis behavior and guiding the selection of suitable conditions for thermochemical valorization.