We study the properties of aggregates or gels consisting of metal-organic or organometallic-conjugated oligomers or polymers. The primary objective of this project is to design metal-containing molecular arrays that self-assemble in solution and to study the triplet exciton migration on these aggregates. Figure 1 shows a few examples of Platinum-acetylide Oligomers which aggregate or gel in hydrocarbon solvents. The molecules stack to form a ordered fibrous network as shown in the TEM images (Figure 2). The triplet-triplet energy transfer within molecular aggregates consisting of phosphorescent platinum-acetylide oligomers is shown in the emission spectroscopy (Figure 3).