9,9-Dimethylxanthene is a heterocyclic building block. 9,9-Dimethylxanthene is suitable for use in the preparation of 9,9-dimethylxanthene-4,5-dicarboxylic acid.It may be used in the preparation of 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene.It may be used in the preparation of 4,6-bis(dimesitylboryl)dibenzofuran. 9,9-Dimethylxanthene is a heterocyclic building block. 9,9-Dimethylxanthene is suitable for use in the preparation of 9,9-dimethylxanthene-4,5-dicarboxylic acid.It may be used in the preparation of 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene.It may be used in the preparation of 4,6-bis(dimesitylboryl)dibenzofuran.