Created/produced by Hanna-Barbera
Frankenstein Jr. and the Impossibles was an animated TV show that aired on CBS on September 10, 1966, until its unfortunate end in 1968 with the rise of censorship and parents complaining about violence in children's cartoons. The show only lasted for two seasons with 18 episodes in total.
Frankenstein Jr. is a crime-fighting robot created by Buzz Conroy, and The Impossibles were also crime fighters but in the form of a Beatles-esque band.
Even though the title promises that Frankenstein Jr. and Buzz would be the titular main characters, this was unfortunately not the case. After the massive success of Scooby-Doo a year later, Hanna-Barbera would go on to create their very own Scooby-Doo clones that would maximize their other cartoons. During this time, Hanna-Barbera Amination Studios was running out of money FAST, and their other IPs were being forgotten. So what did they do? They took new and existing IPs and made them into one big show, called "collections". This practice was very common during the 1960s to the mid to late 1980s to pour the revenue back into Hanna-Barbera Studios.
However, Frankenstein Jr. would interact with The Impossibles through a single-issue comic that was published by Gold Key in 1966.