The reactions of triphenylsilyl-sodium(Ph3SiNa), diphenylmethylsilyl-sodium(Ph2MeSiNa), triphenylsilyl-potassium (Ph3SiK), triphenylsilyl-rubidium (Ph3SiRb), and triphenylsilyl-caesium (Ph3SiCs) with 9-methylfluorene in tetrahydrofuran (THF) were studied using the stop-flow technique at low temperatures. The rate constantk(1 mol−1s−1) depends on the nature of the cation; at −50 °Ckis 11.5 for Ph3SiNa, 29.5 for Ph2MeSiNa, 26.8 for Ph3SiK, 35.6 for Ph3SiRb, and 47.9 for Ph3SiCs. It seems that the organosilylalkali–metal compounds (R3SiM) exist in the form of contact ion-pair and therefore the reactivity of an ion-pair is determined by the Coulombic binding energy of the pair. The thermodynamic constants of activation for these reactions were calculated for −50 °C and compared with the corresponding values of triphenylsilyl-lithium Ph3SiLi reaction with 9-methylfluorene in THF. The plots of log k, ΔS≠, and ΔH≠against 1/(rc + 2) and ΔS≠against ΔH≠were drawn to show that Li+due to its existence as solvent separated ion-pair behaves differently to its Na+, K+, Rb+, and Cs+counterparts.The electronic spectra of R3SiM, 9-methyl-fluoren-9-yl-sodium, -potassium, -rubidium and -caesium were determined at temperatures varying from 20 to −80 °C. A red shift was observed in spectra of R3SiNa at low temperatures; this was attributed to the increase in dipole moment which occurs during the electronic transition. The spectra of 9-methylfluoren-9-yl-sodium, -potassium, -rubidium, and -caesium were compared with their lithium counterpart to explain the effects of gegenion on the solvation of these species.