In 1993, in Lissone, together with his brothers Silvano and Domenico, he opens Spazio Palomar/Space, a showcase for the artisanal production of custom furnishings from the family business. In collaboration with his elder brother, designer Piergiorgio Cazzaniga, originally, Spazio Palomar also serves as an exhibition workshop for a dialogue between fine arts and applied arts. The flyer introducing Spazio Palomar reads: "[it] aims to be an observatory where individual skills can be put to use and where temporary, provisional endpoints can be made known to all." A manifesto of intentions clarified by the very choice of the name, Palomar, the title of one of Italo Calvino's novels and of the namesake Californian astronomical observatory.
Between 1994 and 1995, Spazio Palomar held several exhibitions in collaboration, including the Giorgio Bargna Collection, dedicated to African art, Afghanistan, Lost Territories, showcasing Afghan art and design, in collaboration with Carlo Andermack of Como (flyer Afghanistan), and Niels Hvass Design, a personal show, collateral to the Milan Furniture Fair, featuring prototypes by Danish designer Niels Hvass.
In 1995, Spazio Palomar hosts the inaugural exhibition of Gruppo Koiné, a group co-founded by Mariangelo along with longtime friends Daniele Arosio, Francesco Mariani, and Giacomo Nicola Manenti, among others.
At Spazio Palomar the initial members of the Group meet weekly to discuss perspectives and project ideas. Spazio Palomar thus becomes a laboratory for artistic research and sharing, which will increasingly align, in unity of purpose, with the mission of Gruppo Koiné.
Within this new framework, between 2005 and 2006, Spazio Palomar hosts a series of exhibitions named 13 Interventions, dedicated to the tenth anniversary of Gruppo Koiné; and, from January 2008 onwards, it exhibits, on an annual basis and in conjunction with the Holocaust Remembrance Day, the Gruppo Koiné project Day of Memory.
The year 2011 marks the closure of Spazio Palomar. For this occasion, the members of the Gruppo Koinè gathered together in Spazio Palomar and held the emblematic performance The Last Supper. Mariangelo Cazzaniga has conceived a series of drawings on paper dedicate to this event, called The Last Supper series, part of the Drawings and Collateral Works series.
