Binuclear complexes have attracted extensive attention in fields such as catalysis due to their likely bimetallic synergistic effect. In this work, six bis-β-ketoimine binuclear titanium complexes 4a-4f containing different alkylthio sidearms and different configurations were synthesized and characterized by 1H NMR, 13C NMR, FT-IR and elemental analysis. The intermetallic distances of isomeric complexes 4a, 4d, 4e and 4f determined through DFT optimization were of the order 4a<4d<4e<4f, and were found to influence significantly the catalytic performances for ethylene (co)polymerization. These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity. Among the three binuclear titanium complexes 4a-4c with similar structure but different length of alkylthio sidearms, complex 4a containing the shortest methylthio sidearm exhibited the highest activity for ethylene (co)polymerization and comonomer incorporation, due to a smaller steric hindrance of methyl group in 4a and more open coordination space for vinyl monomers. Furthermore, among isomeric complexes 4a, 4d, 4e and 4f, complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene (co)polymerization, and the highest 1-hexene incorporation in comparison with its regioisomeric counterparts 4d, 4e and p-phenyl-bridged analogue 4f, due to a more appropriate bimetallic distance that is conducive to synergistic effect.