In this study 1-substituted phenyl-3,5-diphenylformazans were synthesized from benzaldehyde-N-phenylhydrazone and appropriate phenyldiazonium salts having CH(3), Br, and Cl at the o-, m-, and p-positions of 1-phenyl ring. Their structures were determined by infrared and ultraviolet-visible spectra. Bathochromic effect in accordance with the electron-donating effect of CH(3), Br, and Cl group and its magnitude were dependent upon type and position of substituent on the ring. The ground-state geometries and absorption wavelengths for 1-phenyl substituted formazans were Studied with density functional theory a rid time-dependent density functional theory. The calculations were carried out by using PBE 1 PBE functional with 6-311G(2d,2p) basis set for lambda(max) of the UV-vis spectra for the studied formazans. A good agreement was obtained between the experimental and computed values. (C) 2009 Elsevier B.V. All rights reserved.