The synthesis of several N-heterocyclic carbene (NHC) group 13 metal adducts of the type (NHC)MR3 [NHC=1,3-bis(2,4,6-trimethylphenypimidazol-2-ylidene (IMes), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IDipp); M=Al, Ga, In; R = Me, Et] is described. In the case of the In adduct (IMes)InMe3, characterization data include its X-ray crystallographic determined molecular structure. The prepared compounds act as efficient ring-opening polymerization (ROP) initiators of rac-lactide, allowing access to either linear poly(lactic acid) (PLA) or cyclic PLA depending on the nature of the initiator and the reaction conditions. For these NHC-MMe3 systems, the addition of benzyl alcohol (acting as a chain transfer agent) was found to be beneficial both to ROP activity and control. In particular, the Al and In systems (IMes)MMe3 (M =Al, In) in combination with BnOH are highly effective ROP initiators of rac-lactide at room temperature (TOF=600 h(-1)). (C) 2016 Elsevier B.V. All rights reserved.