Phosphorescent Pt^II-based cyclometalated complexes co-crystallise with bromo- and iodosubstituted perfluorinated arenes to give 1 : 1 adducts. X-^FArenes in these co-crystals act as both σh and πh donors forming co-operative C-X⋯Cl-Pt XBs and πh⋯d_z2[Pt^II] contacts. The solid-state photophysical study revealed up to a 2-fold luminescence quantum yield increase upon co-crystallisation due to the formation of these co-operative noncovalent interactions.