A facile sol-gel procedure has efficiently fabricated for novel ternary p-n-p g-C3N4 nanosheet/CuBi2O4/Bi3ClO4 nanocomposites. Various techniques such as XRD, EDX, FTIR, XPS, FESEM, TEM, HRTEM, DLS, PL, BET, photocurrent, EIS, UV-Vis DRS, and TGA were adopted to analyze the photocatalysts. The as-prepared nanocomposites were utilized as visible light-induced photocatalysts for photodegradation of rhodamine B as an organic dye and tetracycline hydrochloride as an antibiotic. Among the ternary nanocomposites, the g-C3N4 nanosheet/CuBi2O4/Bi3ClO4 (20:20) shows the most efficient photocatalytic ability toward the degradation of rhodamine B and tetracycline hydrochloride. The results revealed that 98% of rhodamine B and 99% of tetracycline hydrochloride were degraded within 20 and 30 min by photocatalytic reaction, respectively. These results are explained by the formation of p-n-p heterojunction between three semiconductors, more visible light harvesting, and high separation of carrier charges. A possible mechanism is proposed. The superoxide radicals and holes were determined as the important reactive species involved in the photodegradation process. The recycling studies showed that the g-C3N4 nanosheet/CuBi2O4/Bi3ClO4 (20:20) photocatalyst prepared was highly stable and can be recycled and reused up to forth successful cycles without major loss in its photocatalytic ability.