The S-1<--S-0 electronic spectra of 4-dimethylaminobenzonitrile-h(6) and -d(6) (DMABN) and dimethylaniline-h(6) and -d(6) have been reexamined, and new electronic origins have been observed for the -d(6) species, approximately 65 cm(-1) lower in energy than previously reported. The spectra of DMABN-h(3)d(3) and several other isotopomers of DMABN are reported for the first time. A prominent low-frequency progression is assigned to dimethylamino torsion, and the S-1 states are found to be twisted by about 26degrees with a small 190 cm(-1) barrier to planarity. Other bands are tentatively assigned to inversion and methyl torsional motions. (C) 2003 American Institute of Physics.