p-tert-Butyldihomooxacalix[4]arenes,a CH2OCH2 group instead of a methylene bridge of calix[4]arenes,was distinguished with improved conformational mobility and flexibility and additional binding sites from the oxygen bridge.1 Therefore,they exhibited broad complexation properties towards various guests and showedfascinating applications in supramolecular chemistry byintroduction of appropriate functional groups on the phenolic hydroxyls of the lower rim.2 In this work,a series of p-tert-butyldihomooxacalix[4]arenes bearing phenolic hydroxyls and thiourea moieties were prepared to investigate their anion binding behavior.These compounds showed F-binding according to 1H NMR titration experiment.Among them,dihomooxacalix[4]arenes bearing phenyl and benzyl thiourea(2a and 2b)showed multiple interactions with added F-,including N-H…F,O-H…F hydrogen bonds and “through-space” C-H…F-interactions between F-and attached aromatic segment of thiourea.The conformational change of the dihomooxacalix[4]arene cavity has been observed as well and proved by theoretical calculation.The dihomooxacalix[4]arene bearing methyl thiourea(2c)also showed formation of N-H…F,O-H…F hydrogen bonds,but less conformational change of the dihomooxacalix[4]arene cavity according to the 1H NMR titration results.The bis-dihomooxacalix[4]arene(3)showed clear N-H…F hydrogen bond formation upon addition of F-as characterized by 1H NMR spectra.