In order to simulate the effect of non-rubber components on strain-induced crystallization (SIC) in natural rubber (NR), sacrificial metal-ligand bonds are incorporated, for the first time, into cis-1,4 polyisoprene cured by sulfur. The incorporation of sacrificial bonds is found to bring in much smaller onset strain for SIC and higher crystallinity compared with the cis-1,4 polyisoprene with sulfide crosslinks only. Accordingly, the striking improvements in tensile modulus and fracture toughness are achieved. The present work contributes to significant insights for mimicking NR outstanding properties in synthesized cis-1,4 polyisoprene and affords new technological route in improving the mechanical properties of synthesized polyisoprene alternative to the nanofilling. (C) 2016 Elsevier Ltd. All rights reserved.