Phase transfer catalysis (PTC) technique for lower rim alkylation of p-tert-butylthiacalix[4]arene (TCA) with diethyl bromomalonate, phenacyl bromide, N,N-diethylchloroacetamide, ethyl bromoacetate and chloroacetonitrile using K2CO3, CsOH or Na2CO3 as a base and tetraethylammonium bromide (TEAB) as catalyst in benzene has been employed. Selective synthesis of monosubstituted p-tert-butylthiacalixarene using K2CO3 or CsOH as base has been elaborated. Unprecedented alkylation cyclization as well as arene oxidation by using of Na2CO3 as a base for alkylation of p-tert-butylthiacalix[4]arene under PTC conditions led to the synthesis of two new p-tert-butylthiacalix[4]arene derivatives with heterocyclic bridging rings. The structures of the newly synthesized compounds were characterized by different spectroscopy methods IR, 1H NMR, 13C NMR, and single crystal X-ray diffraction