Strong field-induced dissociation by intense mid-infrared pulses was investigated in bromofluoroform monocation (CF3Br+) and iodobenzene dication (C6H5I2+) using ab initio molecular dynamics calculations. In both systems, bond -selective dissociation was achieved using appropriate laser polarizations and wavelengths. For CF3Br+, energetically disfavored fluorine elimination was strongly enhanced at wavelengths of 7 to 8 mu m with polarization along a C-F bond. This is the result of two effects: the deposition of high enough kinetic energy into the molecule by the laser field and the near-resonant excitation of the C-F stretching mode. At shorter and off-resonant wavelengths, bromine elimination becomes significant due to rapid intramolecular vibrational energy redistribution (IVR). For C6H3I2+, the branching ratios for the dissociation of the ortho-, meta-, and para-hydrogens can be controlled simply by changing the laser polarization. These results show the general applicability of bond selective dissociation of cations by intense mid-infrared laser fields.