Nucleophilic substitution of alkyl halides with phenolates (Williamson ether synthesis) traditionally used to synthesize these scaffolds, suffers from functional group incompatibilities due to the harsh conditions it requires. Catalytic strategies for the synthesis of ethers were developed to overcome these drawbacks. Copper can catalyze the coupling of phenols and aryl halides (Ullmann-type reaction), as well as aryl boronic acids and alcohols (Chan-Evans-Lam coupling). Palladium catalyzed O-arylations of alcohols via Buchwald-Hartwig type cross-coupling reactions broaden the substrate scope. Strongly basic conditions and well-designed biaryl phosphine ligands are required for efficient cross-coupling reactions. Nickel catalysis gained increasing interest due to its significantly higher abundance compared to noble metals. The low electronegativity of Ni enables facile oxidative addition into carbon-halide bonds, whereas reductive elimination, especially in case of C-O couplings, is difficult. Thermolysis of Ni(II) oxametallacycles, for example, results in βhydride elimination of undesired carbonyl compounds, whereas oxidation to Ni(III) complexes via single electron transfer (SET) with stoichiometric oxidants can induce reductive elimination resulting in C-O bond formation. Combining nickel with photoredox catalysis, enables the coupling of aryl bromides with alcohols or water without stoichiometric SET oxidants. Photoredox catalysis is dominated by expensive, homogeneous iridium and ruthenium complexes. Noble-metal-free, homogeneous photoredox catalysts, such as borondipyrromethene derivatives (BODIPY), require tedious purification procedures and are prone to degradation. Heterogeneous semiconductors are a recyclable alternative to common homogeneous photoredox catalysts. CdSe quantum dots and CdS were used for carbon-heteroatom couplings via the dual nickel/photoredox catalytic approach. Cadmium, however, is among the most toxic elements and strictly regulated. Its application in the synthesis of APIs is therefore not desirable. Carbon nitride (CN) materials, a class of stable and metal-free semiconductors with low toxicity that can be easily made from commodity chemicals, are able to activate Ni complexes via photosensitization. Here, we show that these materials are also able to catalyze alkyl aryl ether synthesis, likely by triggering reductive elimination via SET modification of the oxidation state of Ni complexes. The etherification of methyl 4-bromobenzoate with 1-hexanol served as a model reaction for initial studies (Table ). A careful optimization of all reaction parameters showed that a carbon nitride material prepared by polymerization of urea and oxamide (CN-OA-m) in combination with catalytic amounts of NiBr 2 •3H 2 O and di-tert-butylbipyridyl (dtbbpy) results the selective synthesis of the desired ether (1) after 48 h irradiation with white LEDs in acetonitrile under mildly basic conditions (entry 1-2). The only side-products were small amounts of the corresponding phenol (2) from the cross-coupling with water, and dehalogenated methyl benzoate (3). In homogeneous dual catalysis, the addition of catalytic amounts of quinuclidine was reported to accelerate the reaction. For similar reasons, an amine-modified organonickel complex was used in combination with photoredox catalysis for the synthesis of phenols from aryl halides and water. The semiheterogeneous protocol did not result in significant rate enhancement when 10 mol% quinuclidine were added (entries 3-4). The utilization of 6,6'-diamino-2,2'-bipyridyl instead of dtbbpy drastically reduced the efficacy of the C-O coupling in our model system (see Table With the optimized conditions in hand, the versatility of the semi-heterogeneous cross-coupling was investigated (Scheme 1). Aryl bromides substituted with electron withdrawing groups in para-position were generally isolated in good to excellent yields. A broad range of functional groups including esters (1), nitriles (4), aldehydes (5), ketones (6, 15), phenylboronic acid pinacol esters (14), chlorides (10), and trifluoromethyl-( ) as well as methylsulfonyl-groups ( ) were tolerated. Substrates with electron withdrawing meta-substituents (7, 8) did also yield the desired products, although with lower efficiency. Ortho-substituted aryl bromides (11, 12)