Polydiacetylenes [C(R)C=CC(R)]n (PDA's) are of interest for their third-order nonlinear optical behaviour and for their thermo- or solvato-chromic properties. We have previously described synthetic and physical studies on soluble PDA's, including polymers with coordinated metal units. We now report the preparation and characterization of new PDA's incorporating polar, hydrogen bonding and metal-containing groups. In this contribution, the following polydiacetylenes will be described: (1) ionic ammonium and phosphonium derivatives and ammonium sulfonate inner salts. (2) adenine- and thymine-substituted polymers with the potential for generation of intermolecular hydrogen bonded species in solution. (3) phosphine- and 2,2'-bipyridyl-containing derivatives and metal complexes derived therefrom. Comparative nonlinear optical studies on selected new materials will be described.