The S-1 <-- S-0 resonance-enhanced ionization spectra are presented for two jet-cooled cyclohexene compounds, 2-(trans-beta-styryl)-1,3,3-trimethylcyclohexene and 1-(trans-beta-styryl)-cyclohexene, in which the cyclohexene ring is formally conjugated to a styryl group. In the trimethyl-substituted derivative, strong steric interactions between the cyclohexene ring and styryl group are present, similar to those found in the retinal system, which significantly influence the ground-state molecular conformation. Both of these styryl cyclohexenes exhibit spectra that are dominated by an intense origin transition, indicating little change in molecular geometry between the two electronic states. In 2-(trans-beta-styryl)-1,3,3-trimethylcyclohexene, two peaks at 34 441 and 34 452 cm(-1) are assigned as origin transitions of different molecular conformations on the basis of power saturation experiments. A relationship between the origin transition energy and the torsional angle of the cyclohexene ring is derived and then used to determine the ground-state equilibrium torsional geometry for both compounds. The two conformations of 2-(trans-beta-styryl)-1,3,3-trimethylcyclohexene are determined to have the cyclohexene ring tilted +/-73 degrees out of the plane of the conjugated styryl system while in 1-(trans-beta-styryl)cyclohexene the cyclohexene double bond is found to be 14-21 degrees from a planar, fully conjugated conformation.