The Domanic oil shale, located in the Volga-Ural petroleum basin, has gained significant attention as a prominent source of unconventional oil recovery in Eastern Europe. However, a comprehensive understanding of the kerogen conversion processes during Domanic shale oil generation remains limited. This paper presents a detailed investigation into the thermal conversion of Domanic oil shale along with the analysis of the resulting oil and gas products using a combination of physicochemical methods and nuclear magnetic resonance (NMR) spectroscopy. The study reveals that the peak oil and gas generation occurs at 350 °C, while kerogen destruction predominantly takes place at 500 °C, leading to the formation of shale gases. Additionally, the research highlights the progressive increase in condensed aromatics within kerogen with rising temperatures, resulting in the formation of higher molecular compounds in the generated oil. Importantly, a strong correlation is observed among the NMR relaxation technique, saturates aromatics resins asphaltenes analysis, and GC-MS method in evaluating the evolution of Kerogen maturity during hydrothermal conversion. The application of the solid echo sequence demonstrates intense NMR signals, indicating the presence of mobile liquid hydrocarbons within the closed pores of kerogen. This hypothesis is further supported by SEM images and GC-MS analysis of aromatic fractions across different temperatures and various studied samples. Overall, this study significantly enhances our understanding of the complex processes involved in kerogen conversion within the Domanic oil shale.