Phthalocyanine derivatives have become very well-known compounds because of their optical, electrical, and magnetic properties. We studied water-dispersible phthalocyanine colloids synthesized using a conventional reprecipitation method. The average phthalocyanine colloid diameter was closely related to the central metal and the peripheral phthalocyanine substituent. The average 4-phenylsulfonylphthalocyanine colloid diameter was much lower than that of 4-phenylsulfinylphthalocyanine because of the larger molecular size of the phthalocyanine macrocycle with sulfonyl substituent. Ni-phthalocyanine with sulphonyl substituent was found to have the lowest diameter of 28.0nm.