Microporous two-phase AIN-SiC composites were prepared using Al4C3 and either Si (N-2 atmosphere) or Si3N4 (Ar atmosphere) as precursors. The reaction mechanisms of the two synthesis routes and the effect of processing conditions on reaction rate and the material microstructures were demonstrated. The exothermic reaction between Si and Al4C3 under N-2 atmosphere was shown to be a simple processing route for the preparation of porous two-phase AIN-SiC materials. The homogeneous two-phase AIN-SiC composites had a grain size in the range of 1-5 mum, and the porosity varied in the range of 36%-45%. The bending strength was 50-60 MPa, in accordance with the high porosity.