Syntheses and single-crystal X-ray structure determinations are reported for a number of adducts of bismuth(III) nitrate with the aromatic bidentate base systems 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen). With bpy, a mononuclear 1:2 adduct is formed, [(bpy)(2)Bi(O2NO)(3)], isomorphous with its rare earth counterparts, orthorhombic, Pbcn, a 16.7634(8), b 8.9970(4), c 15.0099(7) Angstrom, Z = 4, conventional R on \F\ 0.029 for N-o 2502 independent 'observed' reflections. The Bi centre is 10-coordinate with two bidentate N-base ligands and three bidentate nitrate ligands. With phen the 10-coordinate 1:2 adduct [(phen)(2)Bi(O2NO)(3)] was readily obtained, while the 1:1 adduct proved elusive and a hydroxide-bridged dimer [(phen)(ONO2)(2)Bi(mu-OH)(2)Bi(O2NO)(2)(phen)] with eight-coordinate Bi centres was the sole product from all crystallization attempts. [(phen)(2)Bi(O2NO3)(3)] is monoclinic, C2/c, a 11.258(5), b 17.847(4), c 13.044(5) Angstrom, beta 100.78(4)degrees, Z = 4, R 0.063 for N-o 1958, again isomorphous with its rare earth counterparts; [(phen)(ONO2)(2)Bi(mu-OH)(2)Bi(O2NO)(2)(phen)] is triclinic, <P(1)over bar>, a 8.3251(6), b 8.6315(6), c 10.7650(8) Angstrom, alpha 111.120(1), beta 93.486(1), gamma 102.364(1)degrees, Z = 1, dimer, R 0.024 for N-o 2965. In all syntheses, dimethyl sulfoxide (dmso) was used as the supporting solvent; the structure determination of the dmso adduct [(dmso-O)(3)Bi(O2NO)(3)] is also recorded where the Bi centre is nine-coordinate with three bidentate nitrate ligands and three O-bound dmso ligands: monoclinic P2(1)/n, a 11.4136(6), b 12.6682(7), c 13.4959(7) Angstrom, beta 100.209(1)degrees, Z = 4, R 0.026 for N-o 4214.