Black Canary has managed to avoid being romantically pigeon-holed during her long career in comics since 1945.
I believe this is because she was created by Robert Kanigher to be a femme fatale in the mold of those shady ladies in Will Eisner's THE SPIRIT, but Kanigher paired her with the aggressively adolescent Johnny Thunder, so from the start, there was no sexual tension.
What do you do with a sexy character trapped in a tryst with a limp wimp? You cancel the wimp's solo feature and put that sexy lady in a flower shop with a smitten gumshoe!
Her now-solo adventures showed her flirting with raggedy private investigator Larry Lance, but not even the mousey Diana could possibly take Larry seriously, could she?
Well, apparently so, because the next time we see this odd couple they've married and the glamorous Black Canary has retired.
Taking over from Kanigher, Gardner F. Fox paired Black Canary with Starman for two adventures.
We later find out that Canary and Starman had an affair; courtesy of James Robinson and Gene Ha in STARMAN Annual #2; so Fox's attempt to domesticate Canary didn't really take! It was just a matter of time before Canary got rid of that pesky wedding ring and got back into the Dating Game.
A misadventure with a then-clean-shaven Green Arrow resulted in the death of Larry, which threw Canary back into the dating pool.
Kanigher shows up, again, and has her kissing Batman under the Mistletoe, but nobody else thought that this was a good idea. Canary moped around in the Justice League satellite for a good long while as Diana Prince was stuck without her Wonder Woman powers, but as soon as the Amazon was back in town, BAM, the two least powerful Leaguers suddenly decided to get busy after midnight. Not Dr. Midnight, but isn't this a great Alex Toth illustration, anyway?
In 1969, Denny O'Neil came up with the bright idea to have her hook up with Green Arrow. O'Neil gave her a recurring role in the GREEN LANTERN/GREEN ARROW series, expanding their budding romance beyond the awkward embraces that he'd snuck into their Justice League adventures. However, it was in the story WHAT CAN ONE MAN DO?, written by a young fan-turned-pro named Elliot S! Maggin, that showed how close these two heroes had actually become.
Elliot S! Maggin sealed the deal with THE PLOT TO KILL BLACK CANARY, an otherwise-unremarkable tale that moved this couple out of each others' starry-eyed On The Road orbit and deep into the hot tamale jacuzzi of love!
Green Arrow moved from back-up feature to his own title over the next 15 years, mellowing from a bleeding-heart Liberal into a disenchanted Hippie. Green Arrow was 10 years older than all of the other heroes in THE LONG BOW HUNTERS, Mike Grell's 1987 reboot that completely changed the Green Arrow game.
However, as Green Arrow's star rose, Black Canary was thrown under the bus.
Mike Grell first threw cold water into their romance by making Canary unwilling to have children.
Then Grell sealed the deal by torturing her so that she could not have children and also lost her Canary powers.
Green Arrow has since been killed, gotten better, married and divorced Canary. Canary has gotten her powers back but lost Ollie in the process.
Ollie is now getting his freak on, while Dinah is currently looking for love in all the wrong places.
Like the Ross and Rachel romance on the TV show FRIENDS, once you Humpty Dumpty the heat, all the king's horses and all the king's men can't put the egg back together, again: the Black Canary/Green Arrow affair is over, over, over!
But is Black Canary truly radioactive in the romance department?
Having Canary flit from one flirtation to another in BIRDS OF PREY has not resulted in anything substantial, making her forever unlucky in love has not exactly saddled her with a Scarlet Letter! She remains a girl that we want to get her guy, and, clearly, that guy is Oliver Queen.
As the first super hero romance that any of us ever really gave a damn about, Black Canary and Green Arrow must, must, must some day find their way back into each other's arms, by gum!
Those two crazy kids deserve a happy ending! A JUSTICE LEAGUE movie without this love match is not a movie that I want to see!