Using split-pool synthesizing methodology, small molecules produced by DOS make it possible for us to obtain compounds that span a wide chemical space. Here, we discuss cb/cg/cg studies applied to signal transduction, stem cell differentiation and small G-protein researches. All of these studies are conducted not only using biology-oriented libraries but also DOS-oriented libraries. Although cb/cg/cg is a relatively young science that aims the post-genome era sciences, it must bridge chemistry and biology not only in the academia but also in pharmaceutical industries.