•A series of PEG-DILs and PEG-DAILs were synthesized and characterized.•Temperature-dependent biphasic system of PEG1000-DIL/toluene was developed.•Temperature-dependent biphasic system of PEG1000-DAIL/toluene was developed.•The systems were applied in esterification and acetalization in high yields.•The system combined the advantages of homogeneous and heterogeneous catalysis.A novel efficient and recyclable temperature-dependent biphasic catalyst and reaction media combined system comprised of PEG-1000 linked dicationic acidic ionic liquid and toluene was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes with good to excellent yields. This system is characteristic of temperature-dependent reversible biphasic property, simple and facile recyclability, high catalytic activity and extensive substrate and reaction adaptability.A novel efficient and recyclable PEG1000-D(A)IL/toluene temperature driven reversible biphasic system was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes in good to excellent yields.