Dr. Seuss' Halloween is Grinch Night was one of the last specials produced by DePatie-Freleng, and premiered on ABC in 1977, the first Seuss entry to air on a network other than CBS. Now, I've always felt that these primetime offerings could've been repurposed on a Saturday morning closest to Halloween, but the networks never took advantage unless it had to do with a series already established on the Saturday schedule, the notable exception, of course, being Bugs Bunny, since his primetime offerings for CBS were mostly clip shows with a new plot tying everything together.
Anyway, Dr. Seuss and DFE thought it might be a good idea to expand upon the iconic Grinch (voiced this time by Hans Conreid, who had previously starred in a live-action film adaptation of another Seuss story, The 5,000 Fingers of Dr. T), thinking, perhaps rightfully, that Halloween would be the only other holiday that would be perfect for him. See for yourself.
Seuss (Ted Geisel) wrote the lyrics, but the rest of the music was composed by the late Joe Raposo (Sesame Street). Sadly, while Universal, as you can plainly see, bought the rights as part of the deal that enabled them to adapt "How The Grinch Stole Christmas" & "The Cat in the Hat" into live-action feature films, it doesn't appear as though it'll air anywhere over the next week. Of course, I could be wrong about that.
No rating, as I never saw this show, and cannot fairly rate it.