The present invention discloses a co-crystal compound of optical devices. The co-crystal compound is crystallized out with hydrogen bonding by a temperature fluctuation method after mixing small organic molecules without optoelectronic properties and organic molecules having heterocyclic rings with optoelectronic properties. The photoluminescence (PL) intensity of this hydrogen-bonded co-crystal compound according to the present invention can vary with a variety of the small organic molecules without optoelectronic properties, so as to modulate the PL intensity.