Porous conjugated polymers have emerged recently as efficient metal-free and visible light-active photocatalysts. However, the synthesis of this new class of materials usually requires transition metal catalysts such as palladium. A metal-free synthetic route still remains a huge challenge for the chemists. Here we report on a metal-free pathway of a porous conjugated polymer via simple Knoevenagel polycondensation under mild reaction conditions. The obtained polymer exhibited a high surface area and could be applied as a robust and efficient heterogeneous photocatalyst for the oxidative hydroxylation of arylboronic acids under visible light irradiation with a high functional group tolerance of the substrates. (C) 2017 Elsevier Ltd. All rights reserved.