The new sterically hindered scorpionate tris(3-phenylpyrazolyl)methanesulfonate (Tpms(Ph))(-) has been synthesized and its coordination behavior toward a Cu(I) center, in the presence of 1,3,5-triaza-7-phosphaadamantane (PTA), N-methyl-1,3,5-triaza-7-phosphaadamantane tetraphenylborate ((mPTA)[BPh4]) or hexamethylenetetramine (HMT) has been studied. The reaction between Li(Tpms(Ph)) (1) and [Cu(MeCN)(4)][PF6] yields [Cu(Tpms(Ph))(MeCN)] (2) which, upon further acetonitrile displacement on reaction with PTA, HMT, or (mPTA)[BPh4], gives the corresponding complexes [Cu(Tpms(Ph))(PTA)] (3), [Cu(Tpms(Ph))(HMT)] (4), and [Cu(Tpms(Ph))(mPTA)][PF6] (5). All the compounds have been characterized by H-1, P-31, C-13, COSY or HMQC-NMR, IR, elemental analysis, and single crystal X-ray diffraction. In the complexes (3) and (5), which bear a phosphine ligand (i.e., PTA and mPTA, respectively), the new scorpionate ligand shows the typical N,N,N-coordination mode, whereas in (2) and (4), bearing a N-donor ligand (i.e., MeCN and HMT, respectively), it binds the metal via the N,N,O chelating mode, involving the sulfonate moiety.