Complex sentence: It aired on the then-both affiliates of the DuMont Television Network from June 20,1946 to July 1,1947; this made it not only the sole program aired on Thursday nights by DuMont, but also the first "network" television game show.
Split into simpler sentences: It aired on the then-both affiliates of the DuMont Television Network from June 20,1946 to July 1,1947. This made it not only the sole program aired on Thursday nights by DuMont, but also the first "network" television game show.