Series of short story arcs centred upon supernatural entities (Aberrations in Bakemonogatari and Mononoke in Mononoke) taking form and haunting characters. While Mononoke focuses more on the stories and Bakemonogatari on the characters, they structure their short arcs very similarly, both narrative-wise and progression. Both series share this style of storytelling presented with a unique style of animation: Bakemonogatari is more Shaft than the average Shaft, and Mononoke takes upon itself a very "Japanese" style to fit their respective settings.
Both series centre around sequential arcs in which the protagonist tackles a supernatural entity plaguing humans by unravelling the circumstances surrounding it. Bakemonogatari has a modern setting while Mononoke is a period piece, so they complement each other with the contrast.
Both are arc-based stories dealing with one specific supernatural entity in each arc. The true nature of the situation is not always readily apparent at the beginning of the arc but is revealed by the end. They also both have a very distinctive visual style, though not necessarily in the same way.
Both animes are stories about supernatural beings. Bakemonogatari is about oddities and Mononoke is about demons. Both are also made in an unothordox way regarding the animation style and art.
both series feature the same sort of paranormal mystery aspect, though the two go about it in a different timeframe and fashion. Both feature a unique sort of artwork seen in anime, though the two aren't all too similar in that respect.
These two anime are alike for the structure and the very basis of the show. They are both anime about the supernatural separated into arcs. While Mononoke has a better focus on the execution and the art. Bakemonogatari is more character and dialogue based.
Two series about Japanese apparitions. They're not very similar storytelling-wise, but Mononoke's MC (the Apothecary) is quite similar to Oshino Meme, an aberration specialist from Monogatari (they even share the voice actor). If you enjoy encounters with the supernatural, both series should suit you.
Very supernatural, mysterious, Japanese, arc-driven series.
Both have psychedelic art, one of them having it as a basis for the whole anime.
Paying attention is the norm for watching the two series.
One thing though, while both animes have Mystery tags, Mononoke falls more into the horror genre, while the Monogatari series is focused more on romance and fanservice.
Bakemonogatari and Mononoke are surprisingly similar. The latter is definitely more serious, with a heavy psychological focus, whereas the first has no shame in being irreverent and constantly playing around with meta-references (although it never strays into fields of shameless idiocy or exaggerated humor). Both, however, present unique storytelling and a distinctive and highly experimental (Mononoke being much more iconoclastic) audiovisual experience. Words, images, and sounds are just as important as narration in both cases. And in both cases, it never fails to be interesting.
And by far the most interesting connection among them is how the arcs are focused on the characters and their inner
Bakemonogatari and Mononoke feature unique art and direction as well as a lot of dialogue. The shows consist of a series of arcs focused on the supernatural which are well complemented by their music and style.