Photodissociation pathways for 3,4-dichloro-1,2,5-thiadiazole was investigated in its ground state at various wavelengths in the UV region. The photolysis products were identified by the UV absorption and emission spectroscopy. Molecular chlorine (Cl2) elimination was observed using absorption methods in the UV region. UV absorption and quantum calculation confirms the migration of chlorine atom and subsequent ring opening to form NCAC(Cl2)AN@S isomer. Multiphotonic excitation leading to the UV emission in the vicinity of 389 nm was observed due to the formation of CN(B2Σ+) moiety. New UV absorption bands observed at ~255 and ~290 nm were assigned to the its isomer NCAC(Cl2)AN@S.