Executive Summary : | Blazars, subclasses of active galactic nuclei (AGNs), are known for their extreme and energetic behavior, hosting supermassive black holes and a relativistic jet pointing towards Earth. They emit radiation across the electromagnetic spectrum, making them the most luminous and variable sources in the Universe. This research aims to investigate the very high-energy (VHE) emission of blazars, focusing on gamma-ray photons with energies exceeding 100 GeV. The study aims to understand the impact of extragalactic background light (EBL) on VHE photons, which are crucial for extracting intrinsic properties and optimizing redshift estimation techniques for Bl Lac objects. A comprehensive approach combining observational data analysis with advanced theoretical modeling will be used to study VHE emission characteristics, quantify spectral hardening, and explore extra emission processes. Theoretical broadband modeling will explain multi-wavelength spectra of flat-spectrum radio quasars (FsRQs), and a long-term multi-wavelength spectrum and timing study of blazars will provide insights into physical processes and jet dynamics. The research aims to significantly advance our understanding of blazar physics, cosmic evolution, and particle acceleration processes. |