These movies are all from the mid seventies to early eighties, and show off Woody Allen's more serious and philosophical side. They're also funny though, with one big exception.
The only pure drama on this list, and the only pure drama by Allen that I've seen. It's the story of three (though really mostly two) sisters and what they experience after the separation of their parents. They frequently butt heads and have very different takes on their parents, especially how their delicate mother is handing being away from her husband. She dives even deeper into her interior decorating, but it might not be enough to keep her going anymore. The film is very obviously heavily influenced by the style of Ingmar Bergman, and it's mostly a well acted and filmed drama, but I mostly wasn't interested in the characters or their plights. It also seemed just a bit forced in the shots it creates - Bergman was able to create similarly striking images without them seeming so intentional. Still, it's not a bad departure for a guy previously mostly known for silly comedies.
Love and Death
Possibly the last purely goofy Allen movie, Love and Death still has hints of what he would try out later, both in its repeated Bergman references and the constant philosophical debate among its main characters, even if that debate is mostly played for laughs. It's about a Russian played by Allen who stumbles his way to being a war hero, marries his cousin played by Diane Keaton, and eventually they attempt to assassinate Napoleon together. It's a fun little spin on classic Russian literature that manages to be funny throughout without completely ignoring the subject matter it tackles.
A Midsummer Night's Sex Comedy
Yet another Bergman-influenced film (boy, did Allen ever love that guy), and his first collaboration with Mia Farrow. It's about three couples that go on a weekend together to a cottage in the woods in the early 1900s, and end up struggling the whole time with conflicted feelings. Farrow is marrying an older professor, but she had a previous experience with Allen and is very attractive to his other friend. The professor is drawn to the friend's new companion, and Allen also has feelings for Farrow further risking his rocky marriage with Mary Steenburgen. There are some sillier elements like his flying machine and a strange device that can show the past, but it's mostly a very entertaining mix of comedy and romantic turmoil.
Allen claims this film is not autobiographical, those it's easy to see how it could be seen as such, with him starring as a film director who wants to be serious but is constantly told by fans that they prefer his earlier, funnier work. It's again a mix of humor and more serious elements, this time with an occasionally trippy feel. We frequently see snippets of the films his character has made, and they mix with real life and odd dream sequences which make it easy to get a bit lost as far as what the movie is trying to say. It's a pretty divisive film, and I myself was unable to decide whether I really liked it or thought it was too muddled.