A series of new bis (pyrazol-1-yl)methane ligands with organogermyl and organosilyl groups on the methine carbon, MCHPz2(M/Ph3Ge, PhMe2Si, iPr3Si or Me3Si; Pz/3,5-dimethylpyrazole or 3,4,5-trimethylpyrazole), have been prepared by the reactionof bis (pyrazol-1-yl) methyllithium with triphenylgermanium bromide and organosilyl chloride. Treatment of these ligands withW (CO) 5 (THF) in refluxing THF resulted in new heterobimetallic complexes MCHPz2W (CO) 4 as major products, accompanied bypartial decomposition of ligands to yield a certain amount of PzW (CO) 5as by-products. These new ligands and complexes have beencharacterized by 1H-NMR, IR and elemental analysis. The molecular structures of complexes Ph3GeCHPz2W (CO) 4andMe3SiCHPz2W (CO)4 (Pz/3,5-dimethylpyrazole) have been determined by X-ray structure analysis, indicating that bis (pyrazol-1-yl)methanes act as chelating bidentate ligands in these complexes, and organometallic groups lie in the axial position of themethine carbon. # 2002 Elsevier Science B. V. All rights reserved.