Control of light transmittance is important for optoelectronic devices such as smart windows and switchable photodetectors. In particular, that for infrared light can be used for tuning thermal flows through windows. Plasmonic compound nanomaterials are suitable for those devices because of their electrochemically tunable localized surface plasmon resonance (LSPR). We combined CuS nanoplates with MoO3 nanosheets for developing complementary near infrared electrochromic cell. CuS loses its plasmonic absorption (peaked at ∼1100 nm) when it is reduced, as opposed to MoO3, whose absorption at >600 nm is suppressed when it is oxidized. An assembled smart window with rocking-chair type lithium ion transport exhibits wide transmittance changes in the near infrared region.