Producers Tony Ponturo and Fran Kirmser are looking to build a sports dynasty on the most unlikely of locations — Broadway.After finding a measure of success with the football-focused “Lombardi,” which ended a7 1/2-month run on the Rialto last May, the pair have now turned their attention to their latest play, “Magic/Bird,” about the lives of former basketball stars Earvin “Magic” Johnson and Larry Bird, which will bow at the Longacre Theater on April 11. As with “Lombardi,” the producers are taking aim at sports fans — a nontraditional Broadway audience. But this time they’re adding social media to the marketing playbook. With Johnson and Bird as co-producers on the project, there’s been a sharp uptick, for instance, in those following the project on Facebook, according to Kirmser. And Johnson in particular has used Twitter to get out news of the play. Also helpful is the fact that memories of Johnson and Bird, who both retired in the 1990s, are still relatively fresh in fans’ minds; Lombardi, who died in 1970, coached his last game in 1969, placing him outside the recollection of younger fans. “Having the support and input of the two people who the play is based on has been a great plus as we go and market the play to a wide audience,” Kirmser says. “Their advocacy of the project in the business, sports and entertainment community is one of those intangibles that is hard to measure, but certainly makes the story a bit more contemporary than Lombardi.” Producers are attempting to appeal to kids (and their parents), who may have first-hand recollections of the pair, either via classic video or in person. Youth basketball groups, like the Christian Youth Organization (CYO) and Amateur Athletic Union (AAU), and high school sports organizations have all been focal points for marketing pushes. Basketball fans in general also are in the producers’ crosshairs. The Boston Celtics, Bird’s longtime team, sent out a direct mail to season ticket holders, and the National Basketball Assn., which is a marketing partner on the play, has used its internal e-mail lists to promote the show. African-Americans, who according to one 2011 ESPN survey are almost 35% more likely than the overall average to be basketball fans, have also been a target group. The production has hired a firm to specifically reach out to the black community, sending out promotional material to churches and fraternities, as well as to patrons of Harlem’s Apollo Theater. Knowing the stringent demands of hardcore fans, the production is emphasizing authenticity in its marketing efforts. For example, the play’s TV advertising features the voice of longtime sports commentator Marv Albert. The production itself includes authentic NBA uniforms and footage. Rick Horrow, who hosts “Sportfolio” on Bloomberg Television, says that honing in on sports fans should have a positive impact on ticket sales, just as it helped “Lombardi.” “The sweet spot for a football demographic is effectively similar to a basketball demographic,” Horrow says. “It is much easier today than a decade ago to identify (fans) in either sport who will have an interest in buying tickets” to a Broadway play.