High-refractive-index (high-n) polymers (HRIPs) with a high optical transparency are highly needed in advanced optoelectronic devices. In this work, we report the synthesis and characterization of a series of high-n, transparent, totally colorless, and high-sulfur-containing poly(phenylene sulfide)s (PPSs) bearing a triazine unit. Two new triazine monomers T1 and T2 with hydroxyl and tert-butyl acetate side chains, respectively, were designed and synthesized to develop PPSs with high-n and high alkaline solubility. These PPSs were prepared by the single-phase polycondensation from T1/T2 and commercial aromatic dithiols such as 4,4-thiobisbenzenethiol (TBT) and benzene-1,3-dithiol (BDT), achieving very high-n up to 1.7530 at 633 nm, a high optical transparency (T%>90% @400 nm) and low birefringence (n=0.0014-0.0080), and exhibiting high potential on the application of high-n photoresists. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 724-731