The present invention discloses a biocompatible coating composition that can be photo crosslinked when exposed to long wavelength ultraviolet light. The biocompatible coating composition comprises at least one biocompatible polymer having a photoactive moiety covalently attached thereto, and a biologically active molecule having a photoactive moiety covalently attached thereto. The photoactive moiety covalently attached to the biologically active molecule and the photoactive moiety covalently attached to the at least one biocompatible polymer are the same or different, and absorb and respond to ultraviolet light having a wavelength band of about 300 nm or above. Preferably, the photoactive moiety is a chemical moiety derived from thioxanthone. The inventive biocompatible coating composition can be applied on at least a portion of one surface of an article.