The instability of thermosolutal convection coupled with crossdiffusion of an electrically conducting fluid completely confined in an arbitrary region bounded by rigid wall in the presences of a uniform magnetic field applied in an arbitrary direction is investigated. Some general qualitatively results concerning the character of marginal state, stability of oscillatory motions and limitations on the oscillatory motions of growing amplitude are derived. The results for the thermosolutal convection problems with or without the individual consideration of Dufour and Soret effects follow as a consequence.