<a></a><a>As a metal-free conjugated polymer, carbon
nitride (CN) has attracted tremendous attention as heterogeneous
(photo)catalysts. </a><a></a><a>By
following prototype of enzymes, making all catalytic sites of accessible via
homogeneous reactions is a promising approach toward maximizing CN activity,
but hindered
due to </a><a></a><a>the poor insolubility
of CN</a>.
Herein, we report the dissolution of CN in environment-friendly methane sulfonic
acid and the homogeneous photocatalysis driven by CN for the first time with
the activity boosted up to 10-times, comparing to the heterogeneous
counterparts. Moreover, facile recycling and reusability, the <a>hallmark</a> of heterogeneous catalysts, were kept
for the homogeneous CN photocatalyst via reversible precipitation using poor
solvents. It opens new vista of CN in homogeneous catalysis and offers a
successful example of polymeric
catalysts in bridging gaps of homo/heterogeneous catalysis.