Perspirocyclopropanated bicyclopropylidene (6) was prepared in three steps from 7-cyclopropylidenedispiro[188.8.131.52]heptane (4) (24 % overall) or, more efficiently, through dehalogenative coupling of 7,7-dibromotriangulane (15) (82 %). This type of reductive dimerization turned out to be successful for the synthesis of (E)- and (Z)-bis(spiropentylidene) 14 (67 %) and even of the “third-generation” spirocyclopropanated bicyclopropylidene 17 (17 % overall from 15). Whereas the parent bicyclopropylidene 1 dimerized at 180 °C to yield rotane, dimerization of 6 at 130 °C under 10 kbar pressure occured only with opening of one three-membered ring to yield the polyspirocyclopropanated (cyclopropylidene)cyclopentane derivative 19 (34 % yield), and at the elevated temperature the polyspirocyclopropanated 2-cyclopropylidene[3.2.2]propellane derivative 20 (25 % yield). Perspirocyclopropanated bicyclopropylidene 6 and the “third-generation” bicyclopropylidene 17 gave addition of bromine, hydrogen bromide, and various dihalocarbenes without rearrangement. The functionally substituted branched triangulane 28 and branched dichloro-C2v-triangulane 32 were used to prepare the perspirocyclopropanated rotane (D3h-triangulane) 49 (six steps from 6, 1.4 % overall yield) and the C2v-triangulane 51 (two steps from 17, 41 % overall). Upon catalytic hydrogenation, the perspirocyclopropanated bicyclopropylidene 6 yielded 7,7′-bis(dispiro[184.108.40.206]heptyl) (52) and, under more forcing conditions, 1,1′-bis(2,2,3,3-tetramethylcyclopropyl) (53). The bromofluorocarbene adduct 33 of 17 reacted with butyllithium to give the unexpected polyspirocyclopropanated 1,4-di-n-butyl-2-cyclopropylidenebicyclo[2.2.0]hexane derivative 37 as the main product (55 % yield) along with the expected “third-generation” perspirocyclopropanated dicyclopropylidenemethane 38 (21 % yield). Mechanistic aspects of this and the other unusual reactions are discussed. The structures of all new unusual hydrocarbons were proven by X-ray crystal structure analyses, and the most interesting structural and crystal packing features are presented.