Based on density functional theory combined with nonequilibrium Green's function technique, we investigate the spin-polarized transport properties of the cyclooligomeric Mn-phthalocyanine dimer and Fe-phthalocyanine dimer with carbon nanotube electrodes. The results show that the spin-polarized transport properties can be effectively tuned by changing the central transition metal atoms, and the Mn-phthalocyanine dimer system can exhibit large dual spin-rectifying and high-efficiency dual spin-filtering effects simultaneously under the [1,-1] magnetic configuration. The underlying mechanism is analyzed by spin-resolved transmission spectra, molecular projected self-consistent Hamiltonian orbitals and their spatial distribution.