The anionic and neutral ConC2H2 (n = 1-3) dusters were investigated using anion photoelectron spectroscopy and density functional calculations. The adiabatic detachment energies and vertical detachment energies of ConC2H2- (n = 1-3) were determined. Our results show that the most stable geometries of anionic ConC2H2- (n = 1-2) and neutral ConC2H2 (n = 1-3) are composed of ConC2H dusters adsorbing a hydrogen atom on the top or bridge sites of Co-n, whereas Co3C2H2- consists of a five-member ring of Co3C2 carbide adsorbing two hydrogen atoms on two bridge sites of Co-3. The reaction mechanisms show that the inserted isomer HCoC2H can convert into the vinylidene complex Co=C=CH2 via a side-on isomer M-eta(2)-C2H2).