We show that the 750 GeV diphoton excess can be explained by introducing vector-like quarks and hidden fermions charged under a hidden U(1) gauge symmetry. which has a relatively large coupling constant as well as a significant kinetic mixing with U(1)Y. With the large kinetic mixing. the standard model gauge couplings unify around 1017 GeV. https://www.markymarkscott.com/product-category/4-21/