Thomkins cultivated a widespread network of friendships with artists of critical creativity who opposed "official business" and were skeptical of the conventional painting profession and who were not afraid to step over boundaries. The artist's openness to various influences extended from the anarchic ideas of the "Situational International" to the urbanistic "Architechtural Utopia" by Constant. He lived in Essen during the beginning years of the Rhein art scene and, it goes without saying, got involved in the intellectually fresh paradox of the "Fluxus Activists". Friends such as George Brecht and Robert Filliou, Dieter Roth and Jean Tinguely, as well as Karl Gerstner, Erwin Heerich and François Morellet demonstrate an intriguing spectrum of influences. No "style" - "boundaries hinder the flow."

Friends were important contacts and sources of inspiration for Thomkins. The direct and constant exchange of opinions and experiences offered excitement and incentive for the creative process. in response to a question by Serge Stauffer regarding what inspires his work the most, Thomkins said "Reading and commenced work. Conversations and correspondance"

Thomkins shared close friendships above all with fellow artists such as his childhood friend and Duchamp-specialist Serge Stauffer. Others include Daniel Spoerri, whom he met in 1956 and who procured important contacts for him, and the architect Eckhard Schulze-Fielitz. Together, these three individuals influenced Thomkins the most. He maintained an intensive and extensive correspondance with them, as well as with Carlheinz Caspari and the artist Esmérian.

Time and again, he sought to collaborate with other artists. The "Friends" exhibition of 1969 is a testimonial to the willingness of the artist's friends to work together. The theme of the exhibition is the relationship-network of Karl Gerstner, Dieter Roth, Daniel Spoerri, Thomkins and their "friends of friends".