The Collaborative International Dictionary of English v.0.48:

bimetallistic \bimetallistic\ adj.
   of or pertaining to bimetallism.

   Syn: bimetallic.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

bimetallistic
    adj 1: pertaining to a monetary system based on two metals; "in
           a bimetallistic system both gold and silver can
           constitute legal tender" [syn: bimetallistic,
           bimetallic]