The reaction chemistry of the monomeric organo-copper(I) species {[Ti](CCR 1) 2}CuR {[Ti]=(η 5-C 5H 4SiMe 3) 2Ti; R 1=SiMe 3: 1a, R=CH 3; 1b, R=C 6H 5; 1c, R=C 6H 4OMe-4; 1d, R=CC t Bu; 1e, R=CCSiMe 3; R 1= t Bu: 8a, R=CCSiMe 3; 8b, R=CH 3} towards different inorganic and organic reagents is described. On treatment of 1a– 1e with one equivalent of X 2 ( 2a: X=Br, 2b: X=I) selective cleavage of the copper–carbon σ-bond is observed, producing {[Ti](CCSiMe 3) 2}CuX ( 4a: X=Br, 4b: X=I) along with RX (X=Br: 3a, R=CH 3; 3b, R=C 6H 5; 3c, R=C 6H 4OMe-4; 3d, R=CC t Bu; 3e, R=CCSiMe 3; X=I: 3f, R=CCSiMe 3; 3g, R=CC t Bu). Treatment of {[Ti](CCSiMe 3) 2}CuCCR 3 ( 1d: R 3= t Bu, 1e: R 3=SiMe 3) with ICN ( 7) produces {[Ti](CC t Bu) 2}CuCN ( 9) and 3f or 3g. Copper–carbon σ-bond cleavage is also obtained, when 1a or 8b is treated with stoichiometric amounts of HX ( 10a: X=Br, 10b: X=Cl), NH 4Cl or NEt 3HCl. In contrast, a carbon–carbon coupling is observed when {[Ti](CCR 1) 2}CuR ( 1, 8) is reacted with R 2X (R 2=CH 3, CH 2CH 3, CH 2C 6H 5, CCSiMe 3; X=Cl, Br, I) in a 1:1 molar ratio. This yields R 2R and {[Ti](CCR 1) 2}CuX (R 1=SiMe 3: 4a, X=Br; 4b: X=I; 4c: X=Cl; R 1= t Bu: 11a: X=Cl; 11b: X=Br; 11c: X=I). The latter molecules can be transformed into the corresponding starting materials 1 or 8 by their reaction with, e.g., LiR ( 5). However, when aromatic halides, such as IC 6H 4Me-4, are added to {[Ti](CCSiMe 3) 2}CuCCR 3 ( 1d: R 3= t Bu, 1e: R 3=SiMe 3), elimination of Me 3SiCCR 3 takes place and the titanium(IV)–copper(I) acetylide {[Ti](CCSiMe 3)(CCCu)} 2 ( 15) is formed. In addition, organo copper(I) compounds can be considered as key molecules in the decarboxylative bromination of copper(I) carboxylates: heating the copper(I)-carboxylate {[Ti](CCSiMe 3) 2}CuO 2CR 2 ( 6a: R 2=CH 3, 6b: R 2=C 6H 5) to 100°C produces the organo copper(I) species 1a and 1b by loss of CO 2. On treatment of 1a and 1b with equimolar amounts of Br 2, oxidative cleavage of the CuC σ-bond is induced and {[Ti](CCSiMe 3) 2}CuBr ( 4a) as well as R 2Br are formed. Complex 4a can be transformed to the starting material 6a or 6b by subsequent reaction with AgO 2CR 2 (R 2=CH 3, C 6H 5) on precipitation of AgBr. All compounds synthesized were characterized by elemental analysis and spectroscopy (IR, 1H-NMR, 13C{ 1H}-NMR). The organic products were characterized additionally by GC–mass spectrometry.