We have recently discovered evidence for a population of radio-loud quasars that is reddened by dust. The dust is either along the line of sight to the quasars or is associated with the quasars. In the latter case the dust may be in molecular clouds in the quasar’s host galaxy, or in a molecular torus around the nucleus. We are planning to use 3 mm observations to search for molecular absorption lines (CO and HCO⁺) associated with dust at the redshift of these quasars. If any absorption systems are detected we will be able to deduce detailed information about the physical state of the molecular gas, hopefully showing which of the proposed locations of the dust is most likely.