  Out-of-time-order correlators (OTOC) being explored as a measure of quantum
chaos, is studied here in a coupled bipartite system. Each of the subsystems
can be chaotic or regular and lead to very different OTOC growths both before
and after the scrambling or Ehrenfest time. We present preliminary results on
weakly coupled subsystems which have very different Lyapunov exponents. We also
review the case when both the subsystems are strongly chaotic when a random
matrix model can be pressed into service to derive an exponential relaxation to
saturation.
