This chapter covers two new areas of poly(pyrazol-1-yl)alkane chemistry—namely, organopalladium and organoplatinum chemistry and includes their comparisons. Palladium and platinum were involved in the early exploration of poly(pyrazo1-1-y1)borates and poly(pyrazo1-1-y1)alkanes as ligands, and these ligands have subsequently played key roles in the development of organopalladium and platinum chemistry. For example, among the more recent reports is account of allylpalladium chemistry directly related to the initial applications of these ligands. In addition to poly(pyrazol-1-yl)alkanes and -berates, closely related polydentate ligands containing at least one pyrazol-1-yl (pz) group are included, in particular, ligands containing the pyridin-2-yl (py) and N-methylimidazol-2-yl (mim) groups. The poly(pyrazol-1-yl)alkane ligands have been important in the development of the organometallic chemistry of palladium and platinum and recent new applications have included their role in stabilizing hydrocarbylpalladium(1V) compounds and in the synthesis of intramolecular coordination systems, containing tripodal ligands coordinated to platinum(1V). © 1992, Academic Press Inc.