Clara, Lu 'n' Em. It started on a nighttime slot but later on moved to its daytime slot, thus making it the first daytime network radio serial.
Clara, Lu, and Em was the first radio soap opera on radio network. It aired beginning June 16, 1930 over WGN-AM Chicago, Illinois an lasted until 1930s. Then in early 1940s was broadcast on the NBC Blue Network and CBS, finally airing as a syndicated series in 1945.The program became the first network daytime radio serial when it was moved from its original evening time slot to days.
The drama series was about Northwestern University's students, Clara (Louise Starkey), Lu (Isobel Carothers) and Em (Helen King). Their friends suggested they go on the radio, so the trio approached WGN and did their first shows for no pay.