Explore the fascinating world of binary systems across cosmic scales in this astrophysics seminar presentation that delves into how these paired objects interact with their surroundings. Learn about the evolution of binary systems from the initial collapse of molecular clouds into stars to the dramatic mergers of entire galaxies. Discover how binary interactions influence observable stellar populations, affect gravitational wave signatures from supermassive black hole pairs, and generate electromagnetic phenomena during black hole mergers. Gain insights into circumbinary accretion processes, with special focus on supermassive black hole binary systems in the LISA detection band and the developmental stages of stellar-mass black hole binaries within Active Galactic Nuclei (AGN) disks.