Non-covalent molecularly imprinted polymers are applied as sensitive coatings to planar waveguides and mass-sensitive devices for the selective detection of various groups of analytes in the gaseous and aqueous phases. Cavity imprinting in the bulk of the sensor material as well as surface imprinting techniques are used to enrich analytes ranging from sub-nanometres to micrometres in analyte size. The coated devices provide sensitivity to e.g. polycyclic aromatic hydrocarbons, xanthine derivatives, complex coffee samples and whole microorganisms.