Controlling the relative phase shift of coupled oscillators becomes important in various applications. Examples include quadrature phase generation in image reject receivers, high data rate sampling circuits, clock distribution networks, novel associative memory paradigms and phased array systems for beam scanning. In this work, we study the nonlinear dynamics of coupled oscillators from the perspective of both an applied mathematician who would prefer general and abstract models, and also that of an RF circuit designer who would appreciate comprehensive models that capture more subtle details of such systems. We then explain how the nonlinear phase dynamics of a ring of unidirectionally coupled oscillators may be used for mode switching and frequency tuning and present experimental verication of our analysis with a 65nm CMOS prototype chip. We also present a novel way of controlling relative phases of coupled oscillators by using the naturally occurring phases within oscillator cores to generate arbitrary phase shifts between them. Measurement results for a prototype chip fabricated in a standard 130nm CMOS technology veries the theory and paves the way for employing it in the various applications mentioned before and in particular, beamforming at mmwave frequencies. We also study the pattern recognition applications of coupled oscillator networks and propose a new alternative that avoids the impractical all to all coupling between the oscillators. The compact layout and simplicity of our proposed structure makes it readily implementable in any standard CMOS technology to realize a physical pattern classication system with ultra fast processing speed.