In this Communication, we develop a two-step acyclic diene metathesis in situ polymerization/crosslinking method to synthesize uniaxially aligned main-chain liquid crystal elastomers with chemically bonded near infrared absorbing four-alkenyl-tailed croconaine-core cross-linkers: Because of the extraordinary photothermal conversion property, such a soft actuator material can raise its local temperature from 18 to 260 degrees C in 8 s, and lift up burdens 5600 times heavier than its own weight, under 808 nm near-infrared irradiation.