When stoichiometric amounts of Cu(hfac)(2).H2O and 1,4,5-triazanaphthalene (tan) were combined in methanol, green crystals of Cu(hfac)(2)(tan) were formed. Its structure was determined at low temperature (P2(1)/c, a = 8.3308(4) Angstrom, b = 14.8945(7) Angstrom, c = 18.3046(10) Angstrom, beta = 99.298(2)degrees, V = 2241.5(3) Angstrom(3)) and found to consist of a novel kinked-chain arrangement where N atoms on opposite sides of the tan ligand bridge Cu(hfac)(2) moieties together. Long axial Cu-N bonds lead to rather weak (J/k(B) = -0.06(5) K) antiferromagnetic interactions according to a Bonner-Fisher fit of the magnetic susceptibility data. The magnetic behavior demonstrated by Cu(hfac)(2)(tan) contrasts markedly with that of Cu(NO3)(2)(tan), as reported by Hatfield and co-workers, and is attributed to the differing orientations of the Cu d(x2-y2) magnetic orbital.