Various ladder-like structured poly(phenyl-co-methacryl silsesquioxane)s (LPMSQ)s with high molecular weight (M(w) = 10,000 similar to 40,000) were synthesized by direct hydrolysis and polymerization in the presence of base catalyst at 25 degrees C. Synthesized LPMSQs mainly showed ladder-like structure and photo-cure reaction by 100 mW/cm(2) (360 nm) for 10 s without any photo-cure initiators. Chemical composition and structural analysis of the obtained LPMSQs were characterized using (1)H NMR, (29)Si NMR, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and X-ray diffraction (XRD). Physical properties of LPMSQs before and after photcuring were analyzed by Nanoindentation. Surface modulus increased to 8GPa and hardness of thin films increased from 100 to 400 MPa. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5012-5018, 2011