We evaluate weak mass mixing among the neutral heavy mesons with a bottom (Q = - 1 3) or top (Q = + 2 3) quark and CP violation in the framework of six quark V - A models. It is argued that bottom and top mesons may distinguish the Higgs exchange mechanism of CP violation from a complex phase in the quark mass matrix, if bottom and top quark masses are sufficiently different. Estimates of weak mixing and CP violating effects for e+e- experiments at PETRA, PEP and CESR energies are presented. © 1979.