Heathcliff and Marmaduke is a second season that ran for 13 episodes just after the season as Dingbat and the Creeps did. It featured backup segments with fellow comic strip character Marmaduke (although the Marmaduke segments are actually the first to be seen in each half-hour show).
Reruns of the second season (Heathcliff and Marmaduke) were seen occasionally on Boomerang. In 1983, NBC ran the show as a segment on Thunder the Barbarian reruns.
Two years after this show ended, another one based on Heathcliff was produced by DiC Entertainment, which was called simply Heathcliff, although for distinction this series is usually referred to by the expanded title of Heathcliff and the Catillac Cats.
Each episode consists of a six-minute Heathcliff cartoon sandwiched between two six-minute Marmaduke cartoons. Scatman Crothers sang its name theme song. It competed with The Smurfs on NBC.
NOTE: Only six of these episodes are lost, and seven of them are found remaining. Unfortunately, as there are total of 13 shorts for completion, all of these episodes are out of order.