During the civil war he helped preserve national artistic treasures from the destruction of Madrid, and also designed bomb shelters.

He chose not to exhibit his work and was little known until he was finally persuaded to put on a show in Mexico City at the age of 70, when he was acclaimed as a master of modern Mexican art.

[3] At the student's residence in Madrid he became the friend of like-minded young men such as Salvador Dalí, Federico García Lorca, Luis Buñuel and Rafael Alberti.

[4] In 1929 Martí collaborated with Miguel García-Lomas Somoano on the Edificio Vita office building in the University District of Madrid.

[5] In 1930 he again collaborated with García-Lomas on the 8-story Viviendas Castaño, a collective housing building in the Goya barrio of the Salamanca district of Madrid.

[4] He helped prevent some anti-monarchist groups from destroying the royal statues on the Plaza de Oriente, but was a strong supporter of the Republic and a member of the intellectual and artistic circles of Madrid.

[7] During the Spanish Civil War (1936–39) Martí worked for the Ministry of Education in defense of national artistic treasures, and for the Popular Army in construction of bomb shelters.

[7] Martí and the architect José Lino Vaamonde helped transfer the great masterpieces of the Madrid museums to Valencia, where they avoided being destroyed by Franco's artillery and bombers.

[8] Martí organized the company with the Valencian architect Enrique Segarra(it), Arturo Sáenz de la Calzada(es) and the civil engineer Carlos Gaos.

[8] In Mexico Martí became a lifetime friend of several Spanish Republican exiles including the writer Emilio Prados, the philosopher José Gaos, the poets Manuel Altolaguirre and León Felipe, the poster artist Josep Renau and the painters Manuela Ballester(es) and Enrique Climent(es).