The coupling mechanism between an intense (similar to 10(13) W cm(-2), 780 nm) near-infrared radiation field of duration 125 fs with molecules containing 12-28 atoms is considered in this article. The time-of-flight mass spectra are reported for the molecules benzene (C6H6), biphenyl (C12H10), diphenylmethane (C13H12), and diphenylethane (C14H14). The ionization of these molecules is compared with the predictions of a quasistatic tunneling model giving experimental/calculated yields for benzene, biphenyl, diphenylmethane, and diphenylethane of 1:1, 27:257, 59:113, and 134:467, respectively. The model correctly predicts the order of relative ion yields: benzene < biphenyl < diphenylethane. The ionization probabilities are not correlated with those predicted by the Ammosov-Delone-Krainov (ADK) model. The ADK model predicts relative probabilities of 1 (benzene), 11.6 (biphenyl), 3.4 (diphenylmethane), 1.5 (diphenylethane) at a field strength of 1.2 V Angstrom(-1). In addition, comparison of the Keldysh adiabaticity parameter, gamma, to the structure-based adiabaticity parameter, gamma(psi), at 1 V Angstrom(-1) returns ratios for gamma(psi)/gamma of 0.68, 0.35, 0.42, and 0.29 for benzene, biphenyl, diphenylmethane, and diphenylethane. These ratios suggest that tunneling ionization occurs at a lower intensity than that predicted by the Keldysh adiabaticity parameter.