A sequential optimization approach is presented for topology synthesis of bistable compliant frame mechanisms. The truss-element-based approach for design of bistable compliant mechanisms enables us to overcome the difficulties due to local buckling in the optimization process considering geometrical nonlinearity. However, the truss mechanisms has a drawback in practical fabrication; it is impossible to make a singlepiece mechanism because of the existence of pin joints. In this paper, we propose an optimization method for converting a compliant truss mechanism to an equivalent frame mechanism. In our conversion process, some thin elements are placed at the connections as pseudo-joints to adjust the flexibility of the structure. The geometrically nonlinear behavior and the stability of a converted frame mechanism are also investigated. Numerical example demonstrates the effectiveness of our conversion method.