Treatment of [Ru(CO) 2 (PPh 3 ) 2 (THF) 2 ](BF 4 ) 2 with LiTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) in dichloromethane at reflux resulted in the formation of [Ru(CO) 2 (PPh 3 ) 2 (TCNQ)]BF 4 (1). The synthesis of the carbonylhydride compound [RuH(CO)(PPh 3 ) 2 (TCNQ)] 2 (2) was carried out by reaction of RuHCl(CO)(PPh 3 ) 3 and TCNQ or from [RuH(CO)(PPh 3 ) 2 (CH 3 CN) 2 ]PF 6 and LiTCNQ. The preparation of compounds with diphosphines [Ru(dppe) 2 (TCNQ)] 2 TCNQ(ClO 4 ) (3) and [Ru(dppm) 3 TCNQ]ClO 4 (4) is also described. In all cases substitution reactions of labile ligands occurred with formation of compounds with σ-coordinated TCNQ. From IR, UV-vis, 1 H and 3 1 P NMR spectroscopy and FAB mass spectrometric determinations, monomeric and dimeric compounds are proposed.