  We will discuss the evolution of star clusters with an large initial binary
fraction, up to 95%. The initial binary population is chosen to follow the
invariant orbital-parameter distributions suggested by Kroupa (1995). The Monte
Carlo MOCCA simulations of star cluster evolution are compared to the
observations of Milone et al. (2012) for photometric binaries. It is
demonstrated that the observed dependence on cluster mass of both the binary
fraction and the ratio of the binary fractions inside and outside of the half
mass radius are well recovered by the MOCCA simulations. This is due to a rapid
decrease in the initial binary fraction due to the strong density-dependent
destruction of wide binaries described by Marks, Kroupa & Oh (2011). We also
discuss a new scenario for the formation of intermediate mass black holes in
dense star clusters. In this scenario, intermediate mass black holes are formed
as a result of dynamical interactions of hard binaries containing a stellar
mass black hole, with other stars and binaries. We will discuss the necessary
conditions to initiate the process of intermediate mass black hole formation
and the dependence of its mass accretion rate on the global cluster properties.
