In the framework of the Smart City Expo World Congress that will take place in Barcelona on November 15th, the Spanish Photonics Technology Platform, Fotónica21, organizes the Workshop Photonics 4 Smart Cities. The Workshop will count with interventions of representatives of different companies (both companies with a widely consolidated trajectory as SERVEO, as well as SMEs and start-ups with a promising future), whose activity is directly related to light and photonics technologies, and its application in the field of smart cities. Also, funding opportunities offered by initiatives such as PhotonHub Europe and PhotonCat will be presented, to promote support to companies willing to take one step further by incorporating photonics in their innovations.