Abstract: I will present a theory of lateral triple quantum dot system in a triangular geometry. In this setting, the strong Coulomb interaction and the quantum interference effects play important roles in determining the electronic and spin properties. Configuration-interaction method is used to obtain the many-electron eigenstates and the effects of magnetic field will be explained. It will be shown that this system can be used to realize localized spins with tunable interactions by using purely electrical methods. Transport through this system will be discussed in a simple framework based on rate equations.