.This study reports on Co/Co₂MnSn two-phase magnets. The Co/Co₂MnSn two-phase magnet has Co precipitates in a Co₂MnSn Heusler alloy matrix, in which the two phases are exchange-coupled at the phase boundary. The as-casted Co/Co₂MnSn system, which has Co-Mn solid solution precipitates in a Co₂MnSn Heusler alloy matrix, showed that the Co solid solution precipitates are crystallographically coherent and there is exchange coupling at the phase boundary. To form pure Co precipitates by removal of Mn solute atoms in Co- Mn solid solution, annealing was carried out 48 hours at 870^oC. After annealing, the low T_c and low magnetization phase of the Co-Mn solid solution became a high T_c and high magnetization phase of hexagonal Co.