A polymer-bonded polycyclic aromatic hydrocarbon compound of general formula (1): (P—O)x-Q-(Y)w  (1) wherein P represents a polymeric moiety having at least three repeating units which comprise an optionally substituted phenyl ring; Q represents a perylene, quaterrylene or terrylene moiety; Y is selected from (i) halogen and (ii) optionally substituted N-heterocycloaliphatic groups having from 3 to about 8 ring members which are bonded to Q through an N atom, provided that at least one Y represents (ii); x represents an integer of from 1 to 4; w represents an integer of from 1 to 4. Also, are provided processes of producing the compounds, polymers, markings and articles, and methods of authenticating.