  C points, characterized by circular polarization in momentum space, play
crucial roles in chiral wave manipulations. However, conventional approaches of
achieving intrinsic C points using photonic crystals with broken symmetries
suffer from low Q factor and are highly sensitive to structural geometry,
rendering them fragile and susceptible to perturbations and disorders. In this
letter, we report the realization of magneto-optical (MO) bound states in the
continuum (BICs) using a symmetry-preserved planar photonic crystal, achieving
intrinsic at-{\Gamma} C points that are robust against variation in structural
geometry and external magnetic field. MO coupling between two dipole modes
induces Zeeman splitting of the eigenfrequencies, leading to MO BICs and
quasi-BICs with circular eigenstates for high-Q chiral responses. Furthermore,
switchable C point handedness and circular dichroism are enabled by reversing
the magnetic field. These findings unveil a new type of BICs with circular
eigenstates and on-demand control of C points, paving the way for advanced
chiral wave manipulation with enhanced light-matter interaction.
