Twisted or helical shape 1,2-position-connected terazulene and quaterazulene were synthesized. Variable temperature NMR measurements and theoretical calculations of the quaterazulene suggest that the syn-type structure with terminal azulene overlap is more stable. Planar or bent shape fused terazulenes were also synthesized. Nucleus-independent chemical shift (NICS) calculations carried out for the central seven-membered ring of the bent shape fused terazulene showed a positive value, suggesting anti-aromatic properties.