A monomer useful in prepaπng therapeutic compounds includes a diversity element which potentially binds to a target molecule with a dissociation constant of less than 300 11 M and a linker element connected to the diversity element The linker element has a molecular weight less than 500 daltons, is connected, directly or indirectly through a connector, to said diversity element, and is capable of forming a reversible covalent bond or noncovalent interaction with a binding partner of the linker element The monomers can be covalently or non-covalently linked together to form a therapeutic multimer or a precursor thereof.