The synthesis and optical properties of several phosphorescent conjugated poly(phenylene)s contg. cyclometalated square-planar platinum (II) complexes are reported. These electronic polymers were synthesized via Suzuki cross-coupling of a dibromophenylpyridine-ligated Pt(ii) complex with a fluorene diboronic ester. Their optical properties are characterized by relatively strong orange room-temp. phosphorescence with well-resolved vibronic structure in both frozen 2-methyltetrahydrofuran glass and room-temp. fluid soln. Time-resolved phosphorescence spectroscopy has shown that the polymers have excited state lifetimes of approx. 14 $μ$s. These optical properties of the oligomers and polymers are contrasted with those of small model complexes, the optical properties of which have a strong dependence on the identity of the $\beta$-diketonate ligand used. The potential utility of phosphorescent conjugated polymers is illustrated by examn. of the diffusive quenching due to oxygen as a function of mol. structure. [on SciFinder(R)]