The intersection of Human-Computer Interaction (HCI) and Design for Social Innovation (DSI) is reshaping urban art, fostering the concept of Art Cities. This paper examines two community-driven, phygital co-creation cases of Social Computer Interaction. The first is the Museum of Augmented Urban Art (MAUA) in Italy, an urban phygital participatory art movement. Second, an AR co-created collection of community heritage in Rio de Janeiro, Brazil, called Little Africa Augmented Reality Collection. This article explores how Augmented Reality (AR) technology and participatory methodologies enhance urban art forms, generating a new expression platform. We argue that the convergence of Human-Computer Interaction (HCI) and Design for Social Innovation (DSI) extends beyond Smart Cities to Art Cities as a movement toward a humanized urban ecosystem, advancing to a future of better technology.