This paper studies the utility of the processes gamma gamma-->gamma gamma,
gammaZ, and ZZ in searching for sources of CP violation arising from energy
scales beyond the production thresholds of planned future colliders. In th
e context of an effective Lagrangian approach we consider the most general
set of CP odd SU(2)xU(1) operators that give rise to genuinely quartic gaug
e boson couplings which can be probed in 2-->2 scattering processes at a yy
collider. We study each process in detail, emphasizing the complementary i
nformation that is obtained by varying the initial beam polarizations. Fina
lly, we compare our results to other constraints in the literature on CP od
d gauge boson interactions and quartic gauge boson couplings, the search re
aches obtained here are typically stronger and nicely complement previous s
tudies which have focused primarily on W boson, top quark, or Higgs boson p
roduction.