In this talk we consider Boundary Conformal Field Theory (BCFT) and its gravity dual. BCFT is a CFT defined on a manifold with boundaries. They can be used to describe product states in CFTs, which are most disentangled states. In gravity side, these disentanglings lead disappearance of some spacetime regions and appearance of End of The World (ETW) branes. Brane tensions are related to the boundary entropy in BCFT. This setup can also be used to realize single sided black holes in AdS/CFT context. I will talk about these setups, their quantum information theoretic aspects and connection to black hole physics.