I have only 1 day in Barcelona with my wife and kids ages 12 and 14.They are very well behaved.We are looking for a great restaurant for dinner.If money was not an object and I can only have one choice, were should we go.Again my children are great if you are hesitant to recommend a restaurant because of them.Thanks!
You shouldn't have a problem with the kids if they are well behaved. I took my 7 year old to El Celler de Can Roca in Girona (2 star michelin) and they loved her..and she loved them. Chef Joan Roca even took us (with my kid and husband) to tour their kitchens and wine cellar. Even in France where we ate at michelin starred restaurants, they went out of their way to cook more "kid friendly" dishes for her. El Celler cooked her some homestyle pasta and croquetas, Maison Jaune in St. Remy cooked for her lamb (and even cut the meat for her at the table) and of course the desserts!
So the opposite of London..where kids are to be seen, not heard since we couldn't take our nephew out. Didn't take our child there at all....
If it is just for serious food and service, it would be Drolma, innovative without being overboard. If I am traveling with two teenage kids, I would choose Comerc24, sophisticated enough for adults and enough fun/buzz for younger foodies and decent decor thrown in. There are also many recommendations for Barcelona on this board. If you state your preference in food, you'll probably get some great responses.