  We present here a brief overview of our work in developing a convolutionless
quantum master equation approach suitable for mesoscopic sized systems. Our
final equation can be used in the regimes where the golden rule approach is not
applicable. Here we apply the approach to study the electronic relaxation in
several models with the finite number of normal modes. For such mesoscopic
systems the relaxation behavior differs substantially from the simple
exponential relaxation. In particular, the equation shows the appearance of the
recurrence phenomena on a time-scale determined by the slowest mode of the
system. The formal results are quite general and can be used for a wide range
of physical systems. Numerical results are presented for a two level system
coupled to an Ohmic and super-Ohmic baths, as well as for a model of
charge-transfer dynamics between semiconducting organic polymers. In this later
system, we show how both slow and fast phonon modes contribute to the decay of
an exciton across a heterojunction interface.
