High absorption coefficient is absolutely necessary as the amount of light absorbed by the system will have a direct effect on the efficiency of my experiment. Emission around 980 nm is another important criterion.
Large discotic molecules like porphyrins, pthalocyanins etc can solve your purpose. You can also tune the absorption and emission of these molecules by proper substitution with different functional groups. Bodipy is another molecule which can take your absorption and emission into NIR region by proper substitution and extension of conjugation.