Highly Effective and Green Catalytic Approach Toward α , ω ‐Dihydroxy‐Telechelic Poly(trimethylenecarbonate)

α , ω ‐Dihydroxy‐telechelic poly(trimethylenecarbonate), HO‐PTMC‐OH, is synthesized from the controlled “immortal” ring‐opening polymerization (ROP) of trimethylene carbonate under mild conditions (bulk, 60 °C), using ZnEt 2 or, more efficiently, [(BDI)Zn(N(SiMe 3 ) 2 )] (BDI = CH(CMeNC 6 H 3 ‐2,6‐ i Pr 2 ) 2 ) as catalyst precursor, in the presence of a diol HO‐R‐OH (R = (CH 2 ) 2 or CH 2 C 6 H 4 CH 2 ; 0.5–10 equiv. vs Zn) acting both as co‐initiator and chain transfer agent. Alternatively, HO‐PTMC‐OH is prepared upon hydrogenolysis of HO‐PTMC‐OCH 2 Ph, initially prepared from the ROP of TMC using the [(BDI)Zn(N(SiMe 3 ) 2 )]/PhCH 2 OH system, under smooth operating conditions using Pd/charcoal. Well‐defined dihydroxy‐functionalized PTMCs of molar mass ranging from $\overline M _{\rm n}$  = 2 000 to 109 500 g · mol −1 were thus quantitatively obtained and fully characterized by NMR, MALDI‐TOF‐MS and SEC analyses. The versatility of this “immortal” ROP allows the preparation of alike α , ω ‐functional polyester such as linear HO‐poly(lactide)‐OH, as well as star polymers such as the glycerol‐based PTM‐OH 3 .