Nascent laser-ablated lanthanide metal ions, Ln(+), were reacted with cyclohexacarbons, C6H6+2n (n = 0, 1, 2, or 3), and the resulting organometallic complex ions, {Ln(+)}-{CpHq}, were identified by time-of-flight mass spectrometry. Cyclohexane and cyclohexadiene were especially reactive, primarily undergoing one or more dehydrogenations to produce adduct ions corresponding to the benzene and benzyne complexes, {Ln(+)}-{C6H6} and {Ln(+)}-{C6H4}. Also identified as minor products were the "sandwich" complexes, {C6H6}-{Ln(+)}-{C6H6} Carbon-carbon bond activation was generally an unimportant reaction channel, with small yields of {Ln(+)}-{CpHq} for p less than or equal to 5. Significant differences were observed in product yields and distributions between the several Ln(+) studied, providing the following comparative reactivities : Ce-+ greater than or similar to Tb+ greater than or similar to Gd+ approximate to Pr+ greater than or similar to Ho+ greater than or similar to Dy+ greater than or similar to Lu+ > [Sm+/Tm+/Eu+/Yb+ unreactive]. These differences are explained by the metal ion ground state electronic configurations (typically 4f(n-1) 6s(1)) and promotion energies (PE) for excitation of a (nonbonding) 4f electron to a valence 5d orbital. For example, upon reaction with 1,3-cyclohexadiene, Eu+ (PE = 394 kJ mol(-1)) was virtually inert while Tb+ (PE = 38 kJ mol(-1)) produced abundant Tb+.{C6H6}. The distinctive Ln(+) reactivities indicate that most ablated Ln(+) were in the ground or a low-lying (greater than or similar to 0.3 eV) electronic state. Contrasting the reactivities of two or more Ln(+) co-ablated from a multicomponent target circumvented effects of experimental variables and provided especially reliable comparative reactivities. In addition to the primary chemical effects, variations in product abundances with ion velocity indicated enhanced H-2 loss for high-energy ion-molecule collisions.