pi-Conjugated polymers (Poly1-Poly3) containing a 2,2'-bipyridine (bpy) unit were subjected to coordination to nickel and copper dithiolate for the purpose of manipulating the photophysical properties. The absorption maximum peak of Poly1 [maximum wavelength = 446 nm] redshifted by 36 nm upon the coordination of bpy to NiCl2, which produced Poly1-NiCl2. A further bathochromic shift was observed in the spectrum of Poly1-mntNi [mntNi = (maleonitrile dithiolate)nickel; lambda(max) = 499 nm] bearing the dithiolate ligand, which stemmed from the extension of the conjugated system over the nickel dithiolate moiety through the bpy unit. An increase in the [Ni]/[bpy] ratio in Poly1-mntNi rendered the original maximum peak at 446 nm smaller and the lower energy charge-transfer peak at 499 nm larger; the isosbestic points remained at 380 and 475 nm. The green fluorescence (lambda(max) = 504 nm) emitted from Poly1 markedly diminished upon the coordination of nickel dithiolate because of the effective energy transfer. The absorption maximum peak of Poly1-mntNi in chloroform at 499 nm blueshifted to 471 nm when the volume ratio of the chloroform/N,N-dimethylformamide solvent reached 10:90. The coordination of nickel dithiolate to Poly2 and Poly3 also brought about redshifts of the absorption maximum peaks of as much as 55 and 61 nm, respectively. The absorption maximum peak of Poly1-(phenyldithiolate)nickel(pdtNi) (lambda(max) = 474 nm) redshifted by 28 nm in comparison with that of Poly1, whereas the magnitude of the shift of Poly1-bis(thiophenoxide)nickel(btpNi) bearing two thiophenoxide ligands was 20 nm. Poly1-mntCu with a tetrahedral copper center was also investigated. (C) 2004 Wiley Periodicals, Inc.