Organic
cocrystal exhibits excellent photothermal conversion (PTC),
but how the intermolecular interactions of cocrystals regulate the
PTC is obscure. Here, two isomeric donor molecules (phenanthrene and
anthracene) and two electron-withdrawing molecules (7,7,8,8,8-tetracyanodimethylquinone
and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethane) are self-assembled
into the four cocrystals (PTQ, PFQ, ATQ, and AFQ). By changing the
molecular configuration of the donor and the electron-withdrawing
ability of the acceptor, the intrinsic influencing factors of the
intermolecular interaction on the PTC were explored. Under near-infrared
laser (808 nm) irradiation, the PTC efficiencies of PTQ, PFQ, AFQ,
and ATQ are 35.85, 44.74, 57.00, and 60.53%, respectively. Based on
the single-crystal X-ray diffraction, ultrafast time-resolved transient
absorption, and excited-state theoretical calculations, we found that
the π–π stacking in ATQ and AFQ is conducive to
promoting the near-infrared light-harvesting ability and the p−π
interaction of cocrystals can regulate the nonradiative rotation of
−C(CN)2 groups, resulting in a tunable near-infrared
PTC via the isomeric cocrystals. Accordingly, the evaporation rate
of the porous polyurethane-AFQ foam can reach 1.33 kg·m–2·h–1 in the simulated solar-driven water evaporation
system. This work provides a strategy to boost the PTC by the intermolecular
interactions of cocrystal materials.