The synthesis of trans-di(arylalkynyl)diphosphine platinum(II) complexes bearing trialkoxysilane groups is described, as well as the preparation of siloxane-based hybrid materials from organometallic chromophores through a modified sol–gel process. Glass materials prepared from trans-[P(n–Bu)3]2Pt[(C≡C–p–C6H4–C≡C–p–C6H4–CH2O(CO)NH(CH2)3Si(OC2H5)3]2 generally show spectral transmittance, absorption and luminescence similar to that of solutions reported in the literature. Measurements of optical power limiting for the hybrid glass are carried out, and show broadband nonlinear absorption throughout the whole visible wavelength range with clamping values in the range 0.2–7 µJ at 120 mM chromophore concentration. The sol–gel process using urethane-propyltriethoxysilane-functionalized chromophores as precursors appears to be a valid method for formation of robust silicate materials with grafted diarylethynyl Pt(II) complexes for OPL devices.