C-2 Swan band emission (d(3)pi(g) --> a(3)pi(u)) near 517 nm is observed in a solar reactor for fullerene synthesis. On the basis of theoretical considerations and experimentals in the temperature range 3000-3400 K evidence is presented supporting the formation of excited C2 by absorption of solar photons. This phenomenon that we propose to name: solar-induced fluorescence (SIF) is described for the first time. (C) 2002 Elsevier Science B.V. All rights reserved.