Minibody is a class of bispecific fragments, scFv-derived bispecific molecules. It is a bivalent fusion molecule with two scFvs fused to CH3. The scFv targeting antigen A is fused to the N-terminus of one of the CH3 domains and the scFv targeting antigen B to the other CH3. The knob-into-holes technology is used to force to CH3 domains heterodimerization. It can be further stabilized by C-terminal disulfide bonds. The molecule is bispecific and has 1+1 antigen-binding valency. The CH3 domains extend its half-life and stability. The molecule weight of this type of BsAbs is ~75 kDa. Minibody can be designed to different functional antigens and work as dual inhibitors or immune cells engagers.