Improving Light‐Responsive Efficiency of Type II Porous Liquid by Tailoring the Functionality of Host

Abstract Light‐responsive porous liquids (LPLs) attract significant attention for their controllable gas uptake under light irradiation, while their preparation has remained a great challenge. Here we report the fabrication of type II LPLs with enhanced light‐responsive efficiency by tailoring the host's functionality for the first time. The functionality of light‐responsive metal‐organic cage (MOC‐RL, constructed from dicopper and responsive ligands) is modified by introducing the second long‐chain alkyl ligand, producing MOC‐RL‐AL as a new host. A spatially hindered solvent based on polyethylene glycol, IL‐NTf 2 , is designed and can dissolve MOC‐RL‐AL due to the suitable interaction, creating a type II LPL (PL‐RL‐AL). Under light irradiation, the variation in propylene adsorption for PL‐RL‐AL increases by 58.0 % compared to PL‐RL. The enhanced light‐responsive efficiency is caused by easier control in accessibility of internal cavities within MOCs and increased number of external cavities between MOCs and IL‐NTf 2 . This makes PL‐RL‐AL the first LPL with the probability for propylene/propane separation.