Reaction of Ru-3(CO)(12) with the SO2 analog N-sulfinylaniline (PhN=S=O) in refluxing toluene produces Ru-3(CO)(9)(mu(3)-NPh)(mu(3)-S) (1), Ru-3(CO)(9)(mu(3)-NPh)(2) (2), Ru-4(CO)(10)(mu-CO)(mu(4)-eta(2)-SNPh)(mu(4)-S) (3), and Ru-4(CO)(10)(mu-CO)(mu(4)-eta(2)-SNPh)(mu(4)-NPh) (4) in low yields. Treatment of Ru-3(CO)(10)(NCMe)(2) with PhN=S=O at room temperature affords 1 as the major product in good yield, accompanied by CO2 formation. Compounds 1, 3, and 4 were characterized by mass, IR, and H-1 NMR spectroscopy, and their structures were determined by single-crystal X-ray diffraction. Crystal data for 1 : triclinic (), a = 9.585(2) Angstrom, b = 10.151(2) Angstrom, c = 10.555(4) Angstrom, alpha = 92.32(3)degrees, beta = 93.21(3)degrees, gamma = 98.84(2)degrees, Z = 2, R (R(w)) = 0.026 (0.030). Crystal data for 3 : monoclinic (P2(1)/n), a = 8.986(7) Angstrom, b = 13.968(3) Angstrom, c = 19.232(9) Angstrom, beta = 103.06(5) Angstrom, Z = 4, R (R(w)) = 0.025 (0.025). Crystal data for 4 : monoclinic (P2(1)/c), a = 10.319(4) Angstrom, b = 23.354(6) Angstrom, c = 23.329(7) Angstrom, beta = 100.43(3)degrees, Z = 8, R (R(w))= 0.051 (0.040).