Nickel-Catalyzed Cross-Coupling of Aryl Chlorides with Aryl Grignard Reagents N-Heterocyclic Carbenes, Part 27. This work was supported by Aventis R&T, the Deutsche Forschungsgemeinschaft (DFG), the Bayerischer Forschungsverbund Katalyse (FORKAT), Degussa-Hüls AG, and the Fonds der Chemischen Industrie (studentships for V.P.W.B. and T.W.). We thank C. Brossmer, K. Denk, R. W. Eckl, M. G. Gardiner, J. Schwarz, and C.-P. Reisinger for preparation of commercially unavailable ligands used in the screening assay and T. Boussie from Symyx Technologies for helpful discussions. Part 26: V. P. W. Böhm, C. W. K. Gstöttmayr, T. Weskamp, W. A. Herrmann, J. Organomet. Chem. 2000, 595, 186-190.