A comprehensive ab initio study of the four atom silicon carbide clusters SiC3 and Si2C2 using multiconfigurational self-consistent-field wave functions is presented. In contrast to previous studies the global minimum isomer for SiC3 is predicted to be a C∞v linear triplet with a terminal silicon atom. For Si2C2 the global minimum is a rhombic structure, in accordance with previous studies, while the linear triplet Si–C–C–Si is just 1.0 kcal mol⁻¹ higher in energy.