Photodissociation of a series of complexes Mg+-C6H5X (X=H, F, Cl, Br) has been studied. The formation of Mg+ was found to be the predominant dissociation pathway. We monitored the photodissociation product as a function of the excitation wavelength in a broad spectral region. Experiments on the complexes with different halide substitutions showed similar action spectra. This is explained by a similar structure shared by these complexes with Mg+ being above the benzene ring. In the photodissociation of Mg+-(C6H5F), MgF+ is also formed besides Mg+. The action spectra corresponding to these two channels were found to be different, and the MgF+ channel is believed to be from a different isomer. The experimental results are consistent with our quantum ab initio calculations.