Fluorescent Complement is an imperfectly geometric work, formed from repeated warm green dots set against a cool background consisting of a blue central circle fading to a soft green. Early in his career, Anuszkiewicz became known for juxtaposing warm and cool colors in this way in order to play with visual perception, creating a sense of hum or vibration. Anuszkiewicz said of his early works: "[t]hese first paintings that I did were very interesting because of the vibrancy of the color and because of this strong complementary action that you got, fluorescent action and then the alter-image because you got a sort of movement, they actually seemed to move. I played that up by using a lot of small shapes...that would not sit still on the canvas."
Fluorescent Complement is one of the first paintings Anuszkiewicz created in the new abstract style he developed after graduating with his MFA from Yale in 1955 and moving back to Ohio. However, in his own conception of this phase of his career, it was important to move away from the direct influence of Albers as well as the realism of his very earliest paintings: "[t]he minute I was released from that restriction, things started to happen for me and I felt good. For the first time I started doing things. I really could not allow myself to fully use color as I wanted until I got rid of realistic subject matter. I started using just shape, and color became the subject." In a 1976 interview with Paul Cummings, Anuszkiewicz spoke about how the Impressionists and Cezanne influenced him by their placement of warm and cool hues next to one another to make both colors appear more lively: "[t]he colorful thing about Cezanne's work was the manipulation of the warm and cool colors. He was putting a warm shade next to a cool shade which sort of charges those colors up... Then I could also understand Albers's interaction, where a color changes another color."
Fluorescent Complement was the first painting Anuszkiewicz sold in New York City, which catapulted him to fame. It was included in his first solo show, at the Contemporaries Gallery. Near the end of the exhibition, with no sales made, Alfred F. Barr Jr., then director of New York's Museum of Modern Art, bought Fluorescent Complement, after which a slew of prominent collectors, such as Governor Nelson Rockefeller, snapped up paintings, almost selling out the show. Anuszkiewicz's mother was proud of her son's accomplishments, but, as Anuszkiewicz later recounted, when she learned of the success of the show, she told him "that if he had stuck to his earlier realistic style, he would have sold more" Barr exhibited Fluorescent Complement at the end of 1960 at MoMA, along with other newly-acquired work, including those of the 'father' of Op Art, the Hungarian-French artist Victor Vasarely. Anuszkiewicz was impressed with Vasarely's work and realized that there were similarities with his own. However, he said that "a major difference between their work was that Vasarely composed his paintings in patterns of light and dark, while his were planned arrangements of colors."
Fluorescent Complement, like Anuszkiewicz's Contemporaries show as a whole, signaled the early stirrings of the Op Art movement in North America. Anuszkiewicz's paintings stood in marked contrast to the emotional intensity of the Abstract Expressionism which still dominated the New York scene. The Contemporaries works placed contrasting colors within centralized geometric constructions to create a shimmering, shifting effect. Stuart Preston, reviewer for the New York Times, noted in retrospect of the exhibition that: "[s]cientific experimentation" generated "color relationships of the most startling character and with the most unexpected optical consequences...These early abstractions, though tightly controlled, have a sprawling energy that makes them a reasoned equivalence for the freewheeling dynamism of the so-called Action Painters."