The invention discloses a use of a copper (I) coordination polymer. The chemical formula of the copper (I) coordination polymer is [Cu6I2([mu]4-I)2([mu]4-5-phpymt)2]n, wherein 5-phpymt is an anion formed after proton loss of a mercapto group in 5-phenyl-2-mercaptopyrimidine, and n is any positive integer. The coordination polymer can catalyze the conversion of aryl boronic acid compounds into phenolic compounds under the irradiation of visible lights, and has the characteristics of high conversion efficiency, wide application range and mild reaction conditions. The copper (I) coordination polymer is separated from the obtained reaction system through centrifugation after the conversion reaction ends, and can immediately participate in a next round of reaction after being simply washed water; and after the copper (I) coordination polymer is recycled at least five times, the copper (I) coordination polymer still keeps stable, and the catalytic activity is not significantly reduced.