  In the context of texture 4 - zero and texture 5 - zero hierarchical quark
mass matrices, CP violating asymmetry in $B^o_d({\bar B}^o_d) \to \psi K_S$
(sin2$\beta$) has been evaluated by considering quark masses at $m_Z$ scale.
For a particular viable texture 4 - zero mass matrix the range of sin2\beta is:
0.27 - 0.60 and for the corresponding texture 5 - zero case it is 0.31 - 0.59.
Further our calculations reveal a crucial dependence of sin2$\beta$ on light
quark masses as well as the phase in this sector.
