Poly(N-isopropylacrylamide)s (PNIPAM) with low polydispersity and different isotacticity have been synthesized successfully in different compositions of environment-friendly and less toxic methanol-water mixtures by RAFT polymerization in the presence of 0.1 M Yttrium trifluoromethanesulfonate [Y(OTf) 3]. The reactions were successful with high yield in the solvent compositions having mole-fraction of methanol (x m) at or above 0.31. Molecular weights were found to be in between 2.78 × 10 4 – 5.7 × 10 4 and polydispersity index (M w/ M n= 1.11 – 1.37) was close to unity. Isotacticity [meso diad (m), %] of the polymers increased from 55 to 86% with the increase in the x m value from 0.31 to 1.0. The lower critical solution temperature (LCST) of the formed PNIPAMs in water decreased with the increase in their isotacticity.