Reactions of Cp2M(L)(η2‐Me3SiC2SiMe3) (Cp = η5‐cyclopentadienyl) (1‐Ti: M = Ti, no L; 1‐Zr: M = Zr, L = pyridine) with PhN=C(H)–N(H)Ph are discussed, giving for titanium the formation of hydrogen together with the four‐membered TiIII metallacycle Cp2Ti(κ2‐N,N′‐PhN–C(H)–NPh) (2). For zirconium in the same reaction at elevated temperature the ZrIV complex Cp2Zr(H)(κ2‐N,N′‐PhN–C(H)–NPh) (3) and at ambient temperature, as an intermediate for this, the σ‐alkenyl complex Cp2Zr[C(SiMe3)C=CH(SiMe3)](κ2‐N,N′‐PhN–C(H)–NPh)] (4) were formed. Alternatively, metallation of PhN=C(H)–N(H)Ph and its subsequent reaction with [Cp2TiCl]2 gave 2 and with Schwartz's reagent Cp2Zr(H)(Cl) complex 3. Complex 2 reacts with additional Cp2Ti(η2‐Me3SiC2SiMe3) (1‐Ti) but there are no hints for the expected reduction of the PhN=C(H)–N(H)Ph unit to PhN=C=NPh by further C–H bond activation, the formation of hydrogen and products of the assumed unstable intermediate [Cp2Ti(κ2‐N,N′‐Ph–N=C=N–Ph)]. The molecular structure of complex 2 was determined by X‐ray analysis.