Both methyl isocyanide (CH3NC) and acetonitrile (CH3CN) are detected in the interstellar space, and characterized by their rotational spectral lines due to their relatively small molecular size. These molecules thus usually served as valuable interstellar probes, and provide extensive insights into the physical and chemical conditions of the interstellar medium and contribute to our understanding of star formation processes within these cosmic regions. Additionally, they are also detected in Earth's atmosphere. Relevant investigation is important for enhancing our comprehension of their atmospheric behavior, and lays a scientific foundation for air pollution control and risk assessment.