A method of using a photobase generator for attaching a coupling molecule on a surface of an array, comprising: obtaining a substrate of an array comprising a plurality of carboxylic acid groups for linking to a coupling molecule; contacting the substrate with a carboxylic acid activating compound formulation comprising a carboxylic acid activating compound and a solvent; contacting the carboxylic acid activated substrate with a photoactive coupling formulation comprising a coupling molecule, a polymer and a solvent; selectively exposing the photoactive coupling formulation to light; and coupling the coupling molecule to at least one of the plurality of carboxylic acid groups at the selectively exposed area, wherein the photoactive coupling formulation further comprises: (a) a photobase generator comprising a compound of formula (II): wherein is a nitrogen-containing cation comprising X is NH or CH 2 , n is 0 to 3, A ⊝ is or tetraphenylborate, R 6 is hydrogen or -NO 2 ; and (b) the coupling molecule is an amino acid which has a protecting group attached to an amine group; and wherein upon exposure of said photoactive coupling formulation to light, said protecting group is removed from said coupling molecule, and said unprotected coupling molecule binds to at least one of the plurality of carboxylic acid groups that are attached to the carboxylic acid activated substrate, and wherein said coupling step has a coupling efficiency of at least 98.5%; and repeating said contacting and coupling steps above to produce a desired polypeptide at said at least one carboxylic acid group, wherein said coupling step is performed multiple times at different selectively exposed areas on said substrate. obtaining a substrate of an array comprising a plurality of carboxylic acid groups for linking to a coupling molecule; contacting the substrate with a carboxylic acid activating compound formulation comprising a carboxylic acid activating compound and a solvent; contacting the carboxylic acid activated substrate with a photoactive coupling formulation comprising a coupling molecule, a polymer and a solvent; selectively exposing the photoactive coupling formulation to light; and coupling the coupling molecule to at least one of the plurality of carboxylic acid groups at the selectively exposed area, wherein the photoactive coupling formulation further comprises: (a) a photobase generator comprising a compound of formula (II): wherein is a nitrogen-containing cation comprising X is NH or CH 2 , n is 0 to 3, A ⊝ is or tetraphenylborate, R 6 is hydrogen or -NO 2 ; and (b) the coupling molecule is an amino acid which has a protecting group attached to an amine group; (a) a photobase generator comprising a compound of formula (II): wherein is a nitrogen-containing cation comprising X is NH or CH 2 , n is 0 to 3, A ⊝ is or tetraphenylborate, R 6 is hydrogen or -NO 2 ; and wherein is a nitrogen-containing cation comprising X is NH or CH 2 , n is 0 to 3, A ⊝ is or tetraphenylborate, R 6 is hydrogen or -NO 2 ; and (b) the coupling molecule is an amino acid which has a protecting group attached to an amine group; and wherein upon exposure of said photoactive coupling formulation to light, said protecting group is removed from said coupling molecule, and said unprotected coupling molecule binds to at least one of the plurality of carboxylic acid groups that are attached to the carboxylic acid activated substrate, and wherein said coupling step has a coupling efficiency of at least 98.5%; and repeating said contacting and coupling steps above to produce a desired polypeptide at said at least one carboxylic acid group, wherein said coupling step is performed multiple times at different selectively exposed areas on said substrate. <EOS>