The book is fairly new, at most 4 years and it's the start of a series. I know vampires were involved and that the bookstore was open at night but that's about it.
Night Owls by Lauren M. Roy
Night Owls book store is the one spot on campus open late enough to help out even the most practiced slacker. The employees’ penchant for fighting the evil creatures of the night is just a perk…
Valerie McTeague’s business model is simple: provide the students of Edgewood College with a late-night study haven and stay as far away from the underworld conflicts of her vampire brethren as possible. She’s lived that life, and the price she paid was far too high to ever want to return.
Elly Garrett hasn’t known any life except that of fighting the supernatural werewolf-like beings known as Creeps or Jackals. But she always had her mentor and foster father by her side—until he gave his life protecting a book that the Creeps desperately want to get their hands on.
When the book gets stashed at Night Owls for safe keeping, those Val holds nearest and dearest are put in mortal peril. Now Val and Elly will have to team up, along with a mismatched crew of humans, vampires, and lesbian succubi, to stop the Jackals from getting their claws on the book and unleashing unnamed horrors…
It was released in 2014 and has been stated to be part of a series with Grave Matters released in 2015.
Following Nice Girls Don’t Have Fangs, the second in a hilarious, smart, sexy romantic series about an out-of-work librarian who is turned into a vampire.
With her best friend Zeb’s Titanic-themed wedding looming ahead, new vampire Jane Jameson struggles to develop her budding relationship with her enigmatic sire, Gabriel. It seems unfair that she’s expected to master undead dating while dealing with a groom heading for a nuptial nervous breakdown, his hostile werewolf in-laws, and the ugliest bridesmaid dress in the history of marriage.
Night's Master is the 3rd book in Amanda Ashley's Children of the Night series.
Kathy McKenna was sure that the little Midwestern town of Oak Hollow would be isolated enough for safety, but the moment the black-clad stranger walked into her bookstore, she knew she was wrong. Raphael Cordova exudes smoldering power, and his sensual touch draws Kathy into a world of limitless pleasure and unimaginable dangers.
Oak Hollow was supposed to be neutral territory for Supernatural beings. Instead it has become home to an evil force determined to destroy them—and kill any mortal who gets in the way. As leader of the North American vampires, Raphael has always put duty first, but then, no woman ever enthralled him the way Kathy does. And as the enemy’s terrifying plan is revealed, Raphael’s desire could be a fatal distraction for all his kind, and for the woman he has sworn to love forever…
This one is probably the least likely, as it looks like the vampires are the focus of the series with the bookstore owner only showing up in this 2008 entry.
Could it be Mr Penumbra's 24-Hour Bookstore, by Robin Sloan? I don't recall vampires, but there is a secret society and a mystery. It was published in 2012.
Hounded the first book in the Iron Druid Chronicles by Kevin Hearne
Atticus O’Sullivan, last of the Druids, lives peacefully in Arizona, running an occult bookshop and shape-shifting in his spare time to hunt with his Irish wolfhound. His neighbors and customers think that this handsome, tattooed Irish dude is about twenty-one years old—when in actuality, he’s twenty-one centuries old. Not to mention: He draws his power from the earth, possesses a sharp wit, and wields an even sharper magical sword known as Fragarach, the Answerer.
Unfortunately, a very angry Celtic god wants that sword, and he’s hounded Atticus for centuries. Now the determined deity has tracked him down, and Atticus will need all his power—plus the help of a seductive goddess of death, his vampire and werewolf team of attorneys, a bartender possessed by a Hindu witch, and some good old-fashioned luck of the Irish—to kick some Celtic arse and deliver himself from evil.
Points where this matches the description:
- Occult bookstore in which he has a collection of rare magical books
- Main character is owner of said bookstore
- One of his attorneys is a vampire, "friend" and sparring partner
- First book in the series
- Published during the mentioned four year time frame (2011)
What may not fit:
- Open at night - I don't specifically remember the bookstore open at night, but several of the key scenes do occur at night.
Only one point that doesn't quite match, but seems to match on all other details.
This could be the Alex Verus series
Alex is a clairvoyant, who can see the future. He also runs a Magic store. It's not actually a bookstore per se, but a general magic store. If I recall correctly, the store was generally open at odd hours.
The first book in the series (Fated) was published in 2012.
I can't quite recall the status of vampires in the series though. So it may be a miss on that part.